植 物 分 类 学 报 44 (4): 371–392(2006)
Acta Phytotaxonomica Sinica
doi:10.1360/aps050053
http://www.plantsystematics.com
Morphology of leaf epidermis of Calamagrostis s.l.
(Poaceae: Pooideae) in China
1, 2
MA Hai-Ying 1PENG Hua 2WANG Yue-Hua
1
(Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650204, China)
2
(School of Life Sciences, Yunnan University, Kunming 650091, China)
Abstract Calamagrostis Adans. s.l. is a genus with variable definition in which two genera
are often recognized in China: Calamagrostis s.s. and Deyeuxia Beauv. In this study, the leaf
epidermis of five species of Calamagrostis s.s. and 26 species and one variety of Deyeuxia
was examined under light microscopy. Although all the species examined have a Festucoid
type epidermis, a number of variations of some epidermal features exist at the species level.
This includes variation in morphology and wall thickness of intercostal long cells, shape and
distribution patterns of stomata, morphology and distribution patterns of short cells and silica
bodies, morphology, silicification, and distribution of prickles, and presence of micropapillae.
Fifteen qualitative characters of the leaf epidermis were used in a phenetic analysis. No sharp
differences were found between Calamagrostis s.s. and Deyeuxia. However, there are two
major clusters in the UPGMA tree. The first cluster includes species with thick-walled long
cells, frequent short cells and/or prickles and silicified prickles. The second cluster includes
species with thin-walled long cells, infrequent short cells and/or prickles and unsilicified
prickles. The results show that leaf epidermal variation is related with environment, but not
concordant with any of the infrageneric classifications of the genus. Species in the first cluster
are usually distributed at an altitude above 2600 m, while those of the second cluster are
generally distributed at an altitude below 2600 m.
Key words Calamagrostis, Deyeuxia, micromorphology, long cell, short cell, prickle,
silification, micropapillae.
It has been repeatedly confirmed that leaf epidermal features can help to elucidate
taxonomic relationships at different levels (Prat, 1936; Stebbins, 1956; Metcalfe, 1960; Ellis,
1979; Palmer & Tucker, 1981, 1983; Palmer et al., 1985; Palmer & Gerbeth-Jones, 1988;
Dávila & Clark, 1990; Cai & Wang, 1994; Mejia-Saules & Bisby, 2003). However, much of
the literature on grass leaf epidermal micromorphology is based on broad surveys of the
grasses of restricted geographic regions, or representative taxa of major groups (i.e.,
subfamilies, tribes, or genera) and it is common for only one or two or a few species samples
in a genus (Dávila & Clark, 1990). In Pooideae, only a few genera, such as Poa L. and
Festuca L., have been intensively studied with respect to their leaf epidermal
micromorphology (Aiken & Lefkovitch, 1984; Aiken et al., 1985; Ellis, 1986).
Calamagrostis Adans. s.l. belongs to the tribe Aveneae, subfamily Pooideae, Poaceae
(Clayton & Renvoize, 1986). The genus contains about 270 species, and is widespread
throughout the world in temperate regions and on tropical mountains (Clayton & Renvoize,
1986). The Andes Mountains of South America, central Asia and eastern Australia are three
distribution centers of the genus (Tateoka, 1974). Calamagrostis s.l. has long been recognized
as a genus of taxonomic complexity, in which patterns of morphological variation hamper the
———————————
Received: 31 March 2005 Accepted: 12 December 2005
Supported by the National Natural Science Foundation of China, Grant No. 30070051, and Natural Science Foundation of
Yunnan Province, Grant No. 2000C0069M.
372
Acta Phytotaxonomica Sinica
Vol. 44
delimitation of species (Greene, 1984). The genus has been divided on the basis of
morphological features into sections (Koch, 1837; Torges, 1898; Rozevitz, 1934; Tsvelev,
1983) or subgenera (Wassiljev, 1961). Some authors, following the generic delimitation of
Beauvois (1812), treat Calamagrostis s.l. as two genera, Calamagrostis s.s. and Deyeuxia
Beauv. (Rúgolo, 1978; Edgar, 1995; Renvoize, 1998). In China, Keng (1959), Lu (1987) and
Chen (2001) all recognized two genera. However, as Clayton & Renvoize (1986) indicated,
the delimitation of the genus Calamagrostis s.l. is rather artificial and Calamagrostis s.l. is
more widely accepted. In addition, Aniselytron Merr., a small genus only distributed in East
Asia, was once considered a part of Calamagrostis s.l. (Clayton & Renvoize, 1986). However,
recent anatomical work (Ma et al., 2005) and phylogenetic analyses based on cpDNA
sequences (Davis, unpublished data) have both demonstrated that Aniselytron is distinct from
Calamagrostis s.l. and should be excluded from the group. Following most authors in the
world, we recognize Calamagrostis s.l. in our study, but the generic names Calamagrostis s.s.
and Deyeuxia are used because both have long been used in China.
Studies of Calamagrostis s.l. have concentrated on the taxonomic work while anatomical
studies are rather few. Regional taxonomic studies were conducted by early and late workers
(Hooker, 1897; Kearney, 1898; Stebbins, 1930; Rozevitz, 1934; Vickery, 1940; Keng, 1959;
Rúgolo, 1978; Greene, 1980; Tsvelev, 1983; Lu, 1987; Edgar, 1995; Renvoize, 1998; Noltie,
2000; Chen, 2001, 2002; Phillips & Chen, 2003; Soreng, 2003). With respect to anatomy, Prat
(1936), Metcalfe (1960), and Chen et al. (1993) each examined one representative species of
the genus. They all identified the leaf epidermis of Calamagrostis s.l. as Festucoid type.
Türpe (1962) and Escalona (1991) each studied 13 and 14 species from South America, and
they noted abundant variation in epidermal features, such as the morphology and distribution
of short cells and micropapillae, length and distribution pattern of prickles, frequency and
distribution pattern of stomata, and silicification in prickles and short cells, etc. They both
believed that these features are correlated with environmental factors, especially the altitude.
Türpe (1962) classified the species he studied into two groups, those that grow at low
altitudes (1000–2500 m) and those that grow at high altitudes (3000–5000 m). He suggested
that features such as fewer stomata, frequent hairs, and round silica bodies are correlated with
high altitudes.
In China, Lu (1987) recognized 43 species, 15 varieties of Deyeuxia and six species, four
varieties of Calamagrostis s.s. Chen (2001) made a revision of Deyeuxia in which she
recognized 31 species in the genus. The most recent revision (Lu et al., unpublished
manuscript for Flora of China) recognizes 34 species and one variety of Deyeuxia and six
species of Calamagrostis s.s. No infrageneric classification for Calamagrostis s.s. exists,
whereas two have been proposed for Deyeuxia. Keng (1959) divided Deyeuxia into seven
series on the basis of spikelet structure. Chen (2001) classified Deyeuxia into six series based
on both spikelet structure and the distribution pattern: ser. Neglectae (Roshev.) Keng, ser.
Deyeuxia, ser. Scabrescentes Keng, ser. Tripiliferae Keng, ser. Tibeticae Keng, and ser.
Muticae Keng. Chen (2001) also surveyed the leaf epidermis of 30 Deyeuxia species by SEM.
In her study, Chen (2001) found variation in features such as the morphology and distribution
of silica bodies, frequency of prickles, and sinuousness of long cell walls. However, her
descriptions and analyses were insufficient. Light microscope study (LM) of leaf epidermis
has unique strength in observing some structures (Watson, personal communication), so light
microscopy was used in this study. The purpose of the present study is to survey epidermal
features of the leaf blade of Calamagrostis s.s. and Deyeuxia species that occur in China to
see if epidermal features can provide information of taxonomic value or whether these
features are related with environmental factors.
No. 4 MA Hai-Ying et al.: Morphology of leaf epidermis of Calamagrostis s.l. (Poaceae: Pooideae) in China 373
1
Material and methods
Leaves of 72 samples were studied, including five species of Calamagrostis s.s. and 26
species and one variety of Deyeuxia. Some materials were collected from the field by the first
author while others were gathered from herbarium specimens in the Institute of Botany (PE)
and Kunming Institute of Botany (KUN), both of the Chinese Academy of Sciences. The
materials used are listed in Table 1. Deyeuxia species in the list are arranged in series of Chen
(2001). For species classification, we followed that of Lu et al. (unpublished manuscript for
Flora of China).
Leaves from living plants were fixed in FAA in the field. Leaves from herbarium
specimens were boiled in water for ten minutes or more until fully expanded, then treated
with FAA over one day before use. The experiment procedure followed that of Ellis (1979).
Epidermis is prepared by scraping leaves with a razor and then stained in a solution of 1%
safranin (in 50% alcohol). All the leaves used were mature leaves, while the uppermost and
the lowest ones were avoided. To check the constancy of epidermal features, at least two
samples of each species were studied, except for a few specimens in which material was very
limited. Both the abaxial and adaxial epidermis were studied for each species.
The nomenclature follows that of Metcalfe (1960) and Ellis (1979).
2
Results
2.1 Anatomical description of leaf epidermis in Calamagrostis
2.1.1 General features Both adaxial and abaxial epidermis can be divided into costal
zones and intercostal zones. Costal zones are composed of long cells, short cells and prickles.
The adaxial and abaxial costal zones are of little difference in the same species, as indicated in
Figs. 1, 2, 13, 14, 15, 16, 23, 24, and 39, 40. Intercostal zones differ adaxially and abaxially.
Intercostal zones on the adaxial epidermis are composed of long cells, stomata, and bulliform
cells. Usually neither prickles nor short cells occur on adaxial epidermis. Intercostal zones on
abaxial epidermis are made up of long cells and short cells and/or prickles, and no bulliform
cells occur abaxially. Stomata are also found on the abaxial epidermis in some species, but
less frequent than on the adaxial epidermis. Typical epidermal features of the leaf blade are
illustrated in Fig. 1 and Fig. 3, representing adaxial and abaxial epidermis respectively.
Figures of all species (Figs. 1–40) are provided except for D. debilis (Hook. f.) Veldk. because
no high quality figure was obtained for this species. A summary of selected leaf epidermal
features in Calamagrostis s.l. species is listed in Table 2.
According to the nomenclature of Metcalfe (1960), all the species of Calamagrostis s.l.
exhibit a Festucoid type of leaf epidermis: micro-hairs are absent; stomata subsidiary cells are
parallel-sided or low dome-shaped; short cells, over the veins, are mostly in short rows.
2.1.2 Constancy of features within one species At least two samples of each species
were examined to determine the constancy of leaf epidermal features. Within most species,
the morphology of the leaf epidermis is invariant. Each species has a unique combination of
features, making each species different from one another. Infraspecific variation was only
found in two species, C. epigeios (L.) Roth and D. pyramidalis (Host) Veldk. This variation
mainly lies in the size of long cells and distribution patterns of short cells and prickles on
abaxial surface, as well as the frequency of stomata on abaxial epidermis. For C. epigeios, the
leaf from specimen Huanghe River Expedition 1654 has frequent prickles but few short cells
on abaxial epidermis (Fig. 5), the specimen Hexi Expedition 1309 has few prickles but
frequent short cells (Fig. 6), whereas the specimen R. C. Ching 6854 has nearly equal
occurrence of prickles and short cells (Fig. 7). Furthermore, the specimen Huanghe River
374
Acta Phytotaxonomica Sinica
Vol. 44
Table 1 Materials examined
Taxon
Calamagrostis s.s.
C. epigeios (L.) Roth
C. pseudophragmites (Hall. f. ) Koel.
C. hedinii Pilger
C. macrolepis Litv.
C. emodensis Griseb.
Deyeuxia ser. Neglecta (Roshev.) Keng
Deyeuxia sinelatior Keng ex P. C.
Kuo
D. hakonensis (Franchet & Savatier)
Keng
D. neglecta (Ehrh.) Kunth
D. lapponica (Wahlenb.) Kunth
D. sichuanensis (J. L. Yang) S. M.
Phillips & W. L. Chen
D. purpurea (Trin.) Kunth
Deyeuxia ser. Deyeuxia
D. korotkyi (Litv.) S. M. Phillips &
W. L. Chen
D. pyramidalis (Host) Veldk.
D. effusiflora Rendle
Locality
Without precies locality, Gansu, alt.
2900 m (甘肃, 具体地点不详)
Without precise locality
(具体地点不详)
Mt. Dahaishan, Jiangxi (江西大海山)
Funing, Yunnan, alt. 1540 m
(云南富宁)
Without precise locality
(具体地点不详)
Lushui, Yunnan, alt. 2780 m
(云南泸水)
Kunming, Yunnan, alt. 2000 m
(云南昆明)
Golmud, Qinghai, alt. 2700 m
(青海格尔木)
Golmud, Qinghai, alt. 4300 m
(青海格尔木)
Lushui, Yunnan, alt. 2780 m
(云南泸水)
Hongqilewu, Sichuan, alt. 2300 m
(四川洪七勒乌)
Lushi, Henan, alt. 1300 m
(河南卢氏)
Mt. Wugongshan, Jiangxi, alt. 1600
m (江西武功山)
Nei Mongol, alt. 980 m (内蒙古)
Mt. Zhegushan, Barkam, Sichuan,
alt. 3500 m (四川马尔康鹧鸪山)
Khanasi Lake, Xinjiang
(新疆喀那斯湖)
Mt. Zhegushan, Barkam, Sichuan,
alt. 3000 m (四川马尔康鹧鸪山)
Shuajinsi, Hongyuan, Sichuan, alt.
2600 m (四川红原刷经寺)
Ulanqab Meng, Nei Mongol (内蒙乌
兰察布盟)
Jingpo Lake, Heilongjiang, alt. 350 m
(黑龙江镜泊湖)
Qinghe, Xinjiang, alt. 1800 m
(新疆青河)
Xiangcheng, Sichuan, alt. 3500 m
(四川乡城)
Daocheng, Sichuan, alt. 3550 m
(四川稻城)
Lijiang, Yunnan, alt. 2700 m
(云南丽江)
Heqing, Yunnan, alt. 3000 m
(云南鹤庆)
Lushui, Yunnan, alt. 2100 m
(云南泸水)
Dexing, Jiangxi
(江西德兴)
Zhenxiong, Yunnan, alt. 1850 m
(云南镇雄)
Voucher
Hexi Exped. (河西队) 1309, PE
R. C. Ching (秦仁昌) 6854, PE
S. S. Lai (赖书绅) 3806, KUN
S. Z. Wang (王守正) 1014, KUN
Huanghe River Exped. (黄河队)
1654, PE
H. Y. Ma (马海英) 143, KUN
F. T. Wang (汪发缵) 2229, KUN
H. Y. Ma (马海英) 231, KUN
Geobotany Group (地植物组) 40, PE
H. Y. Ma (马海英) 133, KUN
Sichuan Econ. Pl. Exped. (川经队)
1523, KUN
K. M. Liou (刘继孟) 5288, PE
J. S. Yue (岳俊三) 5664, KUN
S. H. Gong (龚诗辉) s.n., PE
H. Y. Ma (马海英) 240, KUN
N. R. Cui (崔乃然) 820541, PE
H. Y. Ma (马海英) 239, KUN
H. Y. Ma (马海英) 246, KUN
C. P. Wang (王朝品) 271, PE
G. S. Zhou et al. (周根生) 32, PE
R. C. Ching (秦仁昌) s.n., PE
H. Y. Ma (马海英) 071, KUN
H. Y. Ma (马海英) 073, KUN
H. Y. Ma (马海英) 129, KUN
H. Y. Ma (马海英) 138, KUN
Bijiang Exped. (碧江队) 1542, KUN
M. X. Nie & S. S. Lai (聂敏祥, 赖书
绅) 5187, KUN
P. H. Yu (禹平华) 1055, KUN
No. 4 MA Hai-Ying et al.: Morphology of leaf epidermis of Calamagrostis s.l. (Poaceae: Pooideae) in China 375
Table 1 (continued)
Taxon
D. himalaica L. Liou ex W. L. Chen
D. nyingchiensis P. C. Kuo & S. L.
Lu
Deyeuxia ser. Scabrescentes Keng
D. scabrescens (Griseb.) Munro ex
Duthie
D. pulchella (Griseb.) Hook. f.
D. rosea Bor.
Deyeuxia ser. Tripiliferae Keng
D. flavens Keng
D. nivicola Hook. f.
D. mazzettii Veldk.
Deyeuxia ser. Tibeticae Keng
D. tianschanica (Rupr.) Bor
Locality
Baoxing, Sichuan, alt. 2700 m
(四川宝兴)
Xiangcheng, Sichuan, alt. 4390 m
(四川乡城)
Nyingchi, Xizang, alt. 3500 m
(西藏林芝)
Voucher
H. Y. Ma (马海英) 257, KUN
H. Y. Ma (马海英) 94, KUN
Qinghai-Xizang Exped. (青藏队)
751126, PE
Nyingchi, Xizang, alt. 3500 m
(西藏林芝)
H. Y. Ma (马海英) 223, KUN
Mt. Laojunshan, Jianchuan, Yunnan,
alt. 2900 m (云南剑川老君山)
Mt. Laojunshan, Jianchuan, Yunnan,
alt. 3800 m (云南剑川老君山)
Daocheng, Sichuan, alt. 3900 m
(四川稻城)
Daocheng, Sichuan, alt. 4000 m
(四川稻城)
Daocheng, Sichuan, alt. 4000 m
(四川稻城)
Xiangcheng, Sichuan, alt. 3500 m
(四川乡城)
Xiangcheng, Sichuan, alt. 3500 m
(四川乡城)
Gyangzê, Xizang, alt. 3900 m
(西藏江孜)
Mt. Zhegushan, Hongyuan, Sichuan,
alt. 4300 m (四川红原鹧鸪山)
H. Y. Ma (马海英) 52, KUN
Mt. Cuieshan, Sichuan (四川崔峨山)
Hongyuan, Sichuan, alt. 3800 m
(四川红原)
Mt. Laojunshan, Jianchuan, Yunnan,
alt. 3900 m (云南剑川老君山)
Mt. Daxueshan, Shangrila, Yunnan,
alt. 4410 m (云南香格里拉大雪山)
Mt. Daxueshan, Shangrila, Yunnan,
alt. 4600 m (云南香格里拉大雪山)
Daocheng, Sichuan, alt. 4700 m
(四川稻城)
Daocheng, Sichuan, alt. 4500 m
(四川稻城)
Mt. Laojunshan, Jianchuan, Yunnan,
alt. 3900 m (云南剑川老君山)
Daocheng, Sichuan, alt. 4000 m
(四川稻城)
Xiangcheng, Sichuan, alt. 3900 m
(四川乡城)
Shangrila, Yunnan, alt. 3500 m
(云南香格里拉)
Mt. Yulongshan, Lijiang, Yunnan,
alt. 3500 m (云南丽江玉龙山)
Heqing, Yunnan, alt. 3000 m
(云南鹤庆)
Ruoqiang, Xinjiang (新疆若羌)
H. Y. Ma (马海英) 54, KUN
H. Y. Ma (马海英) 82, KUN
H. Y. Ma (马海英) 84, KUN
H. Y. Ma (马海英) 86, KUN
H. Y. Ma (马海英) 95, KUN
H. Y. Ma (马海英) 102, KUN
G. X. Fu (傅国勋) 846, PE
H. Y. Ma (马海英) 243, KUN
F. T. Wang (汪发缵) 83225, PE
H. Y. Ma (马海英) 250, KUN
H. Y. Ma (马海英) 56, KUN
H. Y. Ma (马海英) 63, KUN
H. Y. Ma (马海英) 67, KUN
H. Y. Ma (马海英) 69, KUN
H. Y. Ma (马海英) 78, KUN
H. Y. Ma (马海英) 59, KUN
H. Y. Ma (马海英) 74, KUN
H. Y. Ma (马海英) 101, KUN
H. Y. Ma (马海英) 115, KUN
H. Y. Ma (马海英) 127, KUN
H. Y. Ma (马海英) 134, KUN
K. Guo & D. Zheng (郭柯, 郑度)
12316, PE
376
Acta Phytotaxonomica Sinica
Vol. 44
Table 1 (continued)
Taxon
D. kokonorica Keng
D. tibetica Bor. var. przevalskyi
(Tzvel.) P. C. Kuo & S. L Lu
D. holciformis (Jaub. & Spach) Bor.
D. debilis (Hook. f.) Veldk.
D. moupinensis (Franch.)Pilger
Locality
Sênag, Qinghai, alt. 3200 m
(青海石乃亥)
Madoi, Qinghai, alt. 4500 m
(青海玛多)
Baingoin, Xizang, alt. 4650 m
(西藏班戈)
Shuanghu, Xizang, alt. 4800 m
(西藏双湖)
Shuanghu, Xizang, alt. 4900 m
(西藏双湖)
Mt. Galongla., Bomi, Xizang, alt.
3350 m (西藏波密嘎龙拉山)
Tianquan, Sichuan, alt. 1800 m
(四川天全)
Baoxing, Sichuan, alt. 2600 m
(四川宝兴)
Voucher
H. Y. Ma (马海英) 233, KUN
H. Y. Ma (马海英) 235, KUN
Naqu Branch, Qinghai-Xizang
Exped. (青藏队那曲支队) 10611, PE
K. Y. Lang (郎楷永) 9851, PE
K. Y. Lang (郎楷永) 9869, PE
CAS (生态室高原组) 14929, PE
K. C. Kuan (关克俭) 2211, PE
H. Y. Ma (马海英) 256, KUN
Deyeuxia ser. Muticae Keng
D. diffusa Keng
Mt. Diancangshan, Dali, Yunnan, alt. H. Y. Ma (马海英) 148, KUN
2800 m (云南大理点苍山)
Xiaoshao, Kunming, Yunnan, alt. H. Y. Ma (马海英) 157, KUN
2000 m (云南昆明小哨)
Geza, Shangrila, Yunnan, alt. 3500 m H. Y. Ma (马海英) 168, KUN
(云南香格里拉格咱)
D. petelotii (Hitchc.) S. M. Phillips & Heilongtan, Kunming, Yunnan, alt. H. Y. Ma (马海英) 001, KUN
W. L. Chen
2000 m (云南昆明黑龙潭)
Dayao, Yunnan, alt. 2500 m
H. Y. Ma (马海英) 004, KUN
(云南大姚)
D. flaccida (P. C. Keng) Keng ex S. Mt. Emeishan, Sichuan
Zhang 49, PE
L. Lu
(四川峨眉山)
D. yanyuanensis (J. L. Yang) L. Liu
Yanyuan, Sichuan, alt. 2600 m
H. Y. Ma (马海英) 262, KUN
(四川盐源)
PE: Herbarium of Institute of Botany, the Chinese Academy of Sciences; KUN: Herbarium of Kunming Institute of
Botany, the Chinese Academy of Sciences.
Expedition 1654 has very dense stomata on abaxial surface (Fig. 5), while the specimen R. C.
Ching 6854 has much fewer abaxial stomata (Fig. 7), and the specimen Hexi Expedition 1309
has even fewer abaxial stomata (Fig. 6). In D. pyramidalis, variations are found in size of long
cells as well as distribution patterns of short cells and prickles. Leaf from the specimen H. Y.
Ma 71 has large long cells and infrequent prickles (Fig. 2), that from the specimen H. Y. Ma
129 has medium long cells and frequent short cell-prickle pairs (Fig. 3), and that from the
specimen H. Y. Ma 138 has small long cells and frequent short cells (Fig. 4).
2.1.3 Variations among species Among species, little difference is found in features of
the adaxial epidermis whereas most differences are found on the abaxial epidermis. As a
result, most features we describe here are of the abaxial epidermis, only bulliform cells and
adaxial stomata represent features of the adaxial epidermis.
2.1.3.1 Intercostal long cells Intercostal long cells vary in shape, wall thickness, and size
according to species. Intercostal long cells are elongated in all species, five or more times
longer than wide. In most species, intercostal long cells are rectangular in shape with
side-walls parallel to one another. However, in eight species, the side-walls are more or less
inflated outwards, causing the long cells to exhibit a slightly hexagonal shape. This occurs in
D. korotkyi (Fig. 33), D. pulchella (Fig. 34), D. diffusa (Fig. 35), D. lapponica (Fig. 36), D.
effusiflora (Fig. 37), D. flaccida (Fig. 38), D. petelotii (Fig. 40), and D. debilis. It should be
emphasized, however, that the difference between these two types is only slight.
No. 4 MA Hai-Ying et al.: Morphology of leaf epidermis of Calamagrostis s.l. (Poaceae: Pooideae) in China 377
Table 2
Summary of selected leaf epidermal features in Calamagrostis s. l. species
Species
Intecostal
Intercostal
long cells
Short cells/
prickles
Shape Wall
type
R
3
F
R
3
I
R
3
F
R
3
F
R
3
F
R
1
–
R
3
I
R
0
I
R
1
F
R
1
F
R
1
–
H
0
–
R
3
F
H
0
I
R
3
F
R
3
F
R
3
F
H
0
F
R
2
F
R
1
–
R
0
I
R
2
F
R
2
F
R
1
F
R
3
F
Silica
bodies
Silicified
prickles
Stomata
subsidiary
cells
Abaxial Bulliform Microstomata
cells
papillae
Calamagrostis epigeios
IR
+
P
F
R
–
C. macrolepis
S
+
P
F
R
–
C. pseudophragmites
N
+
D
F
R
–
C. emodensis
S
+
D
–
R
–
C. hedinii
N
+
D
F
R
+
Deyeuxia hakonensis
S
–
P
–
R
–
D. sinelatior
S
+
P
–
R
–
D. lapponica
N
+
P
–
H
–
D. sichuanensis
N
+
P
F
H
–
D. neglecta
N
+
P
–
R
–
D. purpurea
N
–
P
–
R
–
D. korotkyi
N
–
P
I
R
–
D. pyramidalis
N
+
P
–
R
–
D. effusiflora
N
–
P
–
H
–
D. himalaica
N
+
P
–
R
–
D. nyingchiensis
N
+
D
–
R
–
D. scabrescens
T
+
P
–
R
–
D. pulchella
S
–
P
I
H
–
D. rosea
S
–
D
F
R
–
D. nivicola
S
–
P
–
R
–
D. flavens
N
+
P
I
R
–
D. mazzettii
T
+
P
–
R
–
D. tianschanica
S
+
P
I
R
–
D. kokonorica
N
+
P
F
R
–
D. tibetica var.
N
+
P
F
R
–
przevalskyi
D. holciformis
R
3
F
S
+
P
F
R
–
D. debilis
H
0
I
–
–
P
–
H
–
D. moupinensis
R
2
I
S
+
P
–
R
–
D. diffusa
H
0
–
–
P
I
H
–
D. flaccida
H
0
I
–
–
P
–
H
–
D. petelotii
H
0
I
–
–
P
–
H
–
D. yanyuanensis
R
0
F
N
–
P
–
R
–
+, present; –, absent; F, frequent; H, hexagonal; I, infrequent; R, rectangular.
Silica bodies: IR, irregular; N, nodular; S, square; T, tall.
Stomata subsidiary cells: D, low dome-shaped; P, parallel.
Long cell wall type: 0, thin and straight; 1, slightly to moderately thickened, straight; 2, slightly to moderately thickened,
sinuous; 3, heavily thickened, sinuous.
Cell wall thickness of long cells varies greatly, covering a full spectrum from thin and
straight to heavily thickened and sinuous. For long cells of slightly hexagonal shape, cell
walls are always thin and straight, never thickened. In the remaining species, cell walls can be
grouped into four types: (1) unthickened, outline straight in D. flavens (Fig. 28) and D.
yanyuanensis (Fig. 19); (2) slightly to moderately thickened, outline straight in D. hakonensis
(Fig. 30), D. sichuanensis (Fig. 17), D. neglecta (Fig. 16), D. purpurea (Fig. 32), D. nivicola
(Fig. 31), and D. kokonorica (Fig. 18); (3) slightly to moderately thickened, outline sinuous in
D. rosea (Fig. 25), D. mazzettii (Fig. 27), D. tianschanica (Fig. 26), and D. moupinensis (Fig.
29); and (4) heavily thickened, outline sinuous in C. epigeios (Figs. 5–7), C. macrolepis (Fig.
9), C. pseudophragmites (Fig. 20), C. emodensis (Fig. 11), C. hedinii (Fig. 21), D. himalaica
(Fig. 15), D. nyingchiensis (Fig. 12), D. scabrescens (Fig. 8), D. tibetica var. przevalskyi (Fig.
22), and D. holciformis (Fig. 23).
Long cell size varies according to species. C. hedinii (Fig. 21) and D. holciformis (Fig.
24) have the shortest long cells with a length about 100 µm. By contrast, D. hakonensis (Fig.
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No. 4 MA Hai-Ying et al.: Morphology of leaf epidermis of Calamagrostis s.l. (Poaceae: Pooideae) in China 379
30) and D. petelotii (Fig. 40) have the longest long cells with a length about 400 µm. Most
species have medium long cells with a length about 130 to 360 µm. D. moupinensis (Fig. 29)
and D. purpurea (Fig. 32) have the narrowest long cells with a width about 10–12 µm. D.
pyramidalis (Fig. 2) has the broadest long cells, about 30 µm in width. Most species have
medium long cells with a width ranging from 15 to 25 µm.
2.1.3.2 Short cells Short cells occur in both costal and intercostal zones and are more
frequent in the costal zones than in the intercostal zones. The short cells in the costal and
intercostal zones are arranged and distributed differently. Short cells in costal zones are
usually elongated in shape and occur in rows (Figs. 1, 3, 5, 6, 7, 11, 19, 27, 29, 33, 40).
Intercostal short cells are generally isodiametric. They are usually solitary or occur in pairs,
sometimes in pairs with prickles, frequent or infrequent. In D. debilis, D. diffusa (Fig. 35),
and D. flaccida (Fig. 38), short cells are absent or very rare throughout the preparation. In
these species, short cells are more or less completely filled with a single silica body.
2.1.3.3 Prickles and silicified prickles Prickles are present in all species. They are
distributed in both costal and intercostal zones, but are more commonly found in the costal
zones. In five species, prickles were very rare or even absent in intercostals zones: D.
hakonensis (Fig. 30), D. nivicola (Fig. 31), D. diffusa (Fig. 35), and D. debilis. Prickles
distributed in intercostals zones were frequent or infrequent in other species.
Prickles are described by both the size of the base and the size of the barb. Following
that of Ellis (1979), prickle base size is compared with the stomata of the same sample. In
most species we surveyed, prickle base size was small, with base shorter than the stomata.
Medium prickles, with base as long as or slightly longer than the stomata, are only found in
five taxa: C. hedinii (Fig. 21), D. flavens (Fig. 28), D. tibetica var. przevalskyi (Fig. 22), D.
holciformis (Fig. 24), and D. moupinensis (Fig. 29). Prickle barb size is estimated by
comparison with the size of the base of the same prickle as seen in surface view (Ellis, 1979).
Having a long barb means a barb that is as long as or longer than the base. By contrast, a short
barb is shorter than the base, and some prickles are unbarbed or unpointed, with slight
asperity. All three sizes of prickle barbs are found in the present study. D. rosea (Fig. 25), D.
tianschanica (Fig. 26) and five other taxa (C. hedinii, D. nivicola, D. tibetica var. przevalskyi,
D. holciformis, and D. debilis) have long barbed prickles. D. sichuanensis (Fig. 17), D.
neglecta (Fig. 16) and D. nyingchiensis (Fig. 12) have prickles that are unbarbed or
unpointed. The other species all have short prickles with a short barb.
Prickles are more or less silicified in 20 taxa: C. epigeios, C. macrolepis, C. hedinii, C.
pseudophragmites, C. emodensis, D. pyramidalis, D. himalaica, D. scabrescens, D.
nyingchiensis, D. holciformis, D. tibetica var. przevalskyi, D. rosea, D. mazzettii, D.
tianschanica, D. moupinensis, D. purpurea, D. effusiflora, D. kokonorica, D. sichuanensis,
and D. flavens. Silica bodies accumulated in prickles are rounded or square in shape.
2.1.3.4 Silica bodies As mentioned above, silica bodies are found in both short cells and
prickles. In costal zones, as short cells are elongated, silica bodies are usually elongated as
well, with a sinuous outline, and little difference is found among species. In intercostals
___________________________________________________________________________________________________
←
Figs. 1–8. Leaf epidermises in Calamagrostis s.l. and Deyeuxia. 1. D. pyramidalis, adaxial epidermis (H. Y. Ma 71). 2.
D. pyramidalis (H. Y. Ma 71). 3. D. pyramidalis (H. Y. Ma 129). 4. D. pyramidalis (H. Y. Ma 138). 5. C. epigeios (Huanghe
River Expedition 1654). 6. C. epigeios (Hexi Expedition 1309). 7. C. epigeios (R. C. Ching 6854). 8. D. scabrescens (H. Y.
Ma 054)
Bc, bulliform cell; cz, costal zone; iz, intercostal zone; lc, long cell; pr, prickle; sc, silica cell; st, stomata.
Scale bar=100 µm.
Note: All the figures present for abaxial epidermises, except that noted as adaxial one.
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zones, silica bodies vary in shape. Four types of silica bodies were recognized in this study:
(1) tall silica bodies, found in D. scabrescens (Fig. 8) and D. mazzettii (Fig. 27); (2) square
silica bodies, found in C. macrolepis (Fig. 9), C. emodensis (Fig. 11), D. hakonensis (Fig. 30),
D. sinelatior (Fig. 10), D. pulchella (Fig. 34), D. rosea (Fig. 25), D. nivicola (Fig. 31), D.
tianschanica (Fig. 26), D. holciformis (Fig. 24), D. moupinensis (Fig. 29), and D. petelotii
(Fig. 40); (3) nodular silica bodies, observed in C. pseudophragmites (Fig. 20), C. hedinii
(Fig. 21), D. lapponica (Fig. 36), D. sichuanensis (Fig. 17), D. neglecta (Fig. 16), D.
purpurea (Fig. 32), D. korotkyi (Fig. 33), D. pyramidalis (Fig. 1), D. effusiflora (Fig. 37), D.
himalaica (Fig. 14), D. nyingchiensis (Fig. 12), D. flavens (Fig. 28), D. kokonorica (Fig. 18),
D. tibetica var. przevalskyi (Fig. 26), and D. yanyuanensis (Fig. 19); and (4) irregular silica
bodies, only observed in C. epigeios (Figs. 5–7).
2.1.3.5 Bulliform cells Bulliform cells are distributed on the adaxial surface only (Figs. 1,
13, 15, 23, 39). The bulliform cells are obviously expanded and the cell walls are very thin.
Bulliform cells are mostly rectangular in shape, while in D. lapponica, D. sichuanensis, D.
effusiflora, D. pulchella, D. debilis, D. diffusa, D. flaccida, and D. petelotii (Fig. 39), the
bulliform cells are more or less hexagonal in shape.
2.1.3.6 Stomata Stomata are generally abundant adaxially, with four, six or eight rows of
stomata per intercostal zone. The stomata rows are adjacent, not separated by files of
intercostal long cells, and there is only one interstomatal cell between successive stomata
(Figs. 1, 13, 15, 23, 39).
In most species, only adaxial stomata are present, while abaxial stomata are also
observed in a number of species. Frequent abaxial stomata are found in nine taxa: C. epigeios
(Figs. 5–7), C. macrolepis (Fig. 9), D. sichuanensis (Fig. 17), D. kokonorica (Fig. 18), C.
pseudophragmites (Fig. 20), C. hedinii (Fig. 21), D. tibetica var. przevalskyi (Fig. 22), D.
holciformis (Fig. 24), and D. rosea (Fig. 25). In these species, the abaxial stomata are
arranged in rows. Five further species have an infrequent distribution of adaxial stomata: D.
flavens (Fig. 28), D. tianschanica (Fig. 26), D. pulchella (Fig. 34), D. korotkyi (Fig. 33), and
D. diffusa (Fig. 35). They exhibit a sparse distribution and are not arranged in rows.
Stomatal subsidiary cells are usually parallel. Low dome-shaped subsidiary cells are only
found in five species: C. pseudophragmites (Fig. 20), C. emodensis (Fig. 11), C. hedinii (Fig.
21), D. nyingchiensis (Fig. 19), and D. rosea (Fig. 25).
Stomata size varies among species. Stomates can be up to 54 µm long in C. macrolepis
(Fig. 9) and as low as 26 µm in D. nyingchiensis and D. holciformis (Fig. 23). Most species
have medium stomata with a length ranging from 35 to 44 µm.
2.1.3.7 Micropapillae Micropapillae are only found in one species, C. hedinii (Fig. 21).
2.1.3.8 Macrohairs Macrohairs are only found in two species, D. pyramidalis and D.
mazzettii, although the macrohairs were only observed in a few samples of these species.
Macrohairs can be lost easily during scraping, so this feature is not reliable.
2.2 Phenetic analyses
Phenetic analyses were applied to all 32 species surveyed. A list of 15 qualitative
characters was defined and used to score comparative epidermal features. It includes six
___________________________________________________________________________________________________
←
Figs. 9–16. Leaf epidermises in Calamagrostis s.l. and Deyeuxia. 9. C. macrolepis (Geobotany group 40). 10. D.
sinelatior (K. M. Liou 5288). 11. C. emodensis (H. Y. Ma 133). 12. D. nyingchiensis (H. Y. Ma 223). 13. D. himalaica
(adaxial epidermis) (H. Y. Ma 94). 14. D. himalaica (H. Y. Ma 94). 15. D. neglecta (adaxial epidermis) (H. Y. Ma 240). 16.
D. neglecta (H. Y. Ma 240).
Scale bar=100 µm.
Note: All the figures present for abaxial epidermises, except those noted as adaxial ones.
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No. 4 MA Hai-Ying et al.: Morphology of leaf epidermis of Calamagrostis s.l. (Poaceae: Pooideae) in China 383
binary and nine multistate characters (Table 3). These characters were used to build a data
matrix (Table 4) on which we could perform the phenetic analyses. The anatomical
terminology follows that of Ellis (1979). Characters used for phenetic analyses only include
those exhibiting variation within the genus and exclude those being constant in the genus. All
characters were unordered and equally weighted. The analyses were conducted with the
computer program PAUP﹡4.0 b10 (Swofford, 2001) using The Unweighted Pair Group
Average Method (UPGMA).
Table 3 Leaf epidermal characters used in the phenetic analyses
————————————————————————————————————————————
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Side walls of long cells parallel to one another, cells rectangular (0); angled outwards, cells hexagonal (1).
End walls of long cells vertical, at right angle to the horizontal walls (0); angled or sloping in relation to the
horizontal walls (1); rounded, cells of the inflated type (2).
Thickness of horizontal and vertical anticlinal walls of long cells unthickened, thin-walled (0), slightly to moderately
thickened, straight (1); slightly to moderately thickened, sinuous (2); heavily thickened, sinuous (3).
Distribution of associated cells to long cells: no short cells between the adjacent long cells (0); single short cells
present between successive long cells (1); single prickles present between successive long cells (2); single short
cells/single prickles present between successive long cells (3); pairs of short cells present between successive long
cells (4); short cell and hook/prickle pairs present between successive long cells (5).
Bulliform cells rectangular in shape (0); hexagonal in shape (1).
Stomatal subsidiary cells parallel-sided (0); low dome-shaped (1).
Distribution of the stomata in each intercostal zone on adaxial epidermis: four rows of stomata (0); six rows of
stomata (1); eight rows of stomata (2).
Distribution of abaxial stomata: absent (0); infrequent (1); frequent (2).
Distribution of intercostal short cells: between all or most of long cells with a short cell or cell pair between them
(0); common between long cells only in the region flanking the costal zone (1); irregular, presence varies for
different areas of the preparation (2); rare throughout the preparation (3).
Prickles base size: small prickles, base shorter than the stomata (0); medium prickles, base as long as or slightly
longer than the stomata (1).
Prickle barb size: long barb, barb as long as or longer than the base (0); short barb, barb shorter than the base (1);
unbarbed or unpointed, insipient sperity (2).
Prickles unsilicified (0); silicified (1).
Distribution of intercostals prickles: absent (0); infrequent (1); frequent (2).
Shape of silica bodies in intercostal short cells or prickles: tall (0); square (1); nodular (2); irregular (3); absent (4).
Micropapillae absent (0); present (1).
————————————————————————————————————————————
The results from the UPGMA clustering method indicate two main clusters, marked as
cluster A and B in Fig. 41. Cluster A includes all the five Calamagrostis species and 16
Deyeuxia species studied, and cluster B consists of the remaining 11 Deyeuxia species. From
the figure, it is clear that the results of UPGMA are not in accordance with the separation of
Calamagrostis s.s. and Deyeuxia. The results also do not support the infrageneric
classification of Chen (2001). No single feature is associated with the split of these two
clusters. However, it can be inferred that grouping is based on a combination of features.
Species in cluster A generally have thick-walled long cells, frequent short cells and/or
prickles, and prickles are generally silicified in this cluster. Species in cluster B usually have
thin-walled long cells, infrequent or rare short cells and/or prickles, and prickles are unsilicified.
___________________________________________________________________________________________________
←
Figs. 17–24. Leaf epidermises in Calamagrostis s.l. and Deyeuxia. 17. D. sichuanensis (H. Y. Ma 239). 18. D.
kokonorica (H. Y. Ma 233). 19. D. yanyuanensis (H. Y. Ma 262). 20. C. pseudophragmites (H. Y. Ma 143). 21. C. hedinii
(H. Y. Ma 231). 22. D. tibetica var. przevalskyi (H. Y. Ma 235). 23. D. holciformis (adaxial epidermis) (K. Y. Lang 9851).
24. D. holciformis (K. Y. Lang 9851).
Scale bar=100 µm.
Note: All the figures present for abaxial epidermises, except that noted as adaxial one.
384
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No. 4 MA Hai-Ying et al.: Morphology of leaf epidermis of Calamagrostis s.l. (Poaceae: Pooideae) in China 385
Table 4
Distribution of characters among Calamagrostis s.l. species
Characters
1
2
Calamagrostis epigeios
0
0
C. macrolepis
0
0
C. pseudophragmites
0
0
C. emodensis
0
0
C. hedinii
0
0
Deyeuxia hakonensis
0
1
D. sinelatior
0
0
D. lapponica
1
1
D. sichuanensis
0
0
D. neglecta
0
0
D. purpurea
0
1
D. korotkyi
1
2
D. pyramidalis
0
0
D. effusiflora
1
1
D. himalaica
0
0
D. nyingchiensis
0
0
D. scabrescens
0
0
D. pulchella
1
1
D. rosea
0
0
D. nivicola
0
1
D. flavens
0
1
D. mazzettii
0
1
D. tianschanica
0
1
D. kokonorica
0
0
D. tibetica var. przevalskyi
0
0
D. holciformis
0
0
D. debilis
1
0
D. moupinensis
0
0
D. diffusa
1
1
D. flaccida
1
2
D. petelotii
1
2
Note: The matrix is generated from Table 3.
3
3
3
3
3
3
1
3
0
1
1
1
0
3
0
3
3
3
0
2
1
0
2
2
1
3
3
0
2
0
0
0
4
3
1
2
5
3
0
1
2
2
2
3
2
3
4
2
5
5
2
2
4
2
2
3
2
2
2
3
1
0
2
0
5
0
0
0
0
0
0
0
1
1
0
0
0
0
1
0
0
0
1
0
0
0
0
0
0
0
0
1
0
1
1
1
6
0
0
1
1
1
0
0
0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
7
0
0
1
2
1
0
0
0
1
0
0
0
2
2
2
2
0
0
0
0
0
0
0
0
0
2
0
1
0
0
2
8
2
2
2
0
2
0
0
0
2
0
0
1
0
0
0
0
0
1
2
2
1
0
1
2
2
2
0
0
1
0
0
9
0
0
0
0
0
2
0
1
0
0
1
2
0
0
0
0
0
0
0
0
0
2
0
0
0
0
3
0
3
0
3
10
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
1
0
0
0
1
1
0
1
0
0
0
11
1
1
1
1
0
1
1
1
2
2
1
1
1
1
1
2
1
1
0
0
1
1
0
1
0
0
0
1
1
1
1
12
1
1
1
1
1
0
1
1
1
1
0
0
1
0
1
1
1
0
0
0
1
1
1
1
1
1
0
1
0
0
0
13
2
1
2
2
2
0
1
1
2
2
1
0
2
1
2
2
2
2
2
0
1
2
2
2
2
2
1
1
0
1
1
14
3
1
2
1
2
1
1
2
2
2
2
2
2
2
2
2
0
1
1
1
2
0
1
2
2
1
4
1
4
4
1
15
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Stomatal shape and distribution patterns are not associated with the grouping of species.
3
Discussion
3.1
Comparison with previous studies
Our observations of intercostal long cells are somewhat different from those of Chen
(2001). She described long cells of all species as thick-walled, while we found unthickened
walls in ten species: D. lapponica, D. korotkyi, D. effusiflora, D. pulchella, D. flavens, D.
debilis, D. diffusa, D. flaccida, D. petelotii, and D. yanyuanensis. Among these, D. lapponica
and D. petelotii were described with sinuous walls, while we found they are straight-walled.
___________________________________________________________________________________________________
←
Figs. 25–32. Leaf epidermises (all abaxial) in Deyeuxia. 25. D. rosea (H. Y. Ma 243). 26. D. tianschanica (K. Guo & D.
Zheng 12316). 27. D. mazzettii (H. Y. Ma 74). 28. D. flavens (H. Y. Ma 250). 29. D. moupinensis (H. Y. Ma 256). 30. D.
hakonensis (Z. S. Yue 3664). 31. D. nivicola (H. Y. Ma 63). 32. D. purpurea (G. S. Zhou et al. 32).
mp, micropapillae.
Scale bar=100 µm.
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No. 4 MA Hai-Ying et al.: Morphology of leaf epidermis of Calamagrostis s.l. (Poaceae: Pooideae) in China 387
Fig. 41. UPGMA dendrogram of Calamagrostis s.l. species based on leaf epidermal features.
Three species with thickened sinuous cell walls in her study were found thickened but
straight-walled in our study: D. hakonensis, D. neglecta, and D. purpurea. The difference
might result from the fact that we applied LM in our study while she used SEM.
Chen (2001) mentioned the stomata on the abaxial epidermis but provided no details. In
the present study, abaxial stomata were observed in 14 species. In nine of them, abaxial
stomata have a frequent distribution and are arranged in rows as those on adaxial epidermis.
In the other five species, the abaxial stomata exhibit a sparse distribution and are not arranged
in rows.
___________________________________________________________________________________________________
←
Figs. 33–40. Leaf epidermises in Deyeuxia. 33. D. korotkyi (R. C. Ching s.n.). 34. D. pulchella (H. Y. Ma 82). 35. D.
diffusa (H. Y. Ma 148). 36. D. lapponica (N. R. Cui 820541). 37. D. effusiflora (H. Y. Ma 257). 38. D. flaccida (Zhang 49).
39. D. petelotii (adaxial epidermis) (H. Y. Ma 001). 40. D. petelotii (H. Y. Ma 001).
Scale bar=100 µm.
Note: All the figures present for abaxial epidermises, except that noted as adaxial one.
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Vol. 44
Two types of stomata were observed in our study according to subsidiary cells: parallel
and low dome-shaped. The second type was not noted in the previous studies on Chinese
species.
Prickles of various lengths, barbs, and distributions were found. A notable feature about
prickles is the common occurrence of the accumulation of silica. This was observed in 20
species in the present study. Silicified prickles were observed previously in South American
species (Escalona, 1991) but not mentioned by Chen (2001). Our observation is the same as
that of Escalona but not that of Chen (2001).
Micropapillae were not previously observed in Chinese Deyeuxia species (Chen et al.,
1993; Chen, 2001). Our present study did not find micropapillae in any of the Deyeuxia
species but did find them in one Calamagrostis species, C. hedinii. Micropapillae were also
found in South American species in which various types were observed (Escalona, 1991).
According to this study, all variation observed in South American species (Türpe, 1962;
Escalona, 1991) was also observed in Chinese species. This includes variation in shape, size,
and wall thickness of long cells, the morphology and distribution of short cells and silica
bodies, shape and distribution of stomata, morphology and distribution of prickles,
silicification of prickles, and presence of micropapillae, etc.
3.2 Limited taxonomic value at generic level and infrageneric level
Although leaf anatomical features have long been accepted as taxonomically valuable,
very few intensive studies on one genus have been conducted. As a result, anatomical features
have been mainly valued at the subfamily level (Ellis, 1986). Limited studies show that
anatomical criteria play only a minor role in defining the tribes and subtribes and in delimiting
genera (Connor, 1960; Macfarlane & Watson, 1982; Aiken & Lefkovitch, 1984; Aiken et al.,
1985). However, this is partly due to the insufficient study at the generic level. Most of the
large grass genera have not been adequately sampled on a worldwide basis. Further sampling
of larger genera is needed to establish the degree of anatomical variation existing at the
generic level (Ellis, 1986).
Despite being one of the largest genera in the Poaceae, anatomical studies on
Calamagrostis s.l. are rather few. Our survey on leaf epidermis included most species of
Calamagrostis s.l. in China. Patterns of leaf epidermal variation in this genus were examined
and recorded. Numerous variations were found among species, and it was observed that each
species has its own unique combination of features, making the species different from one
another. As a result, the leaf epidermal features provide some taxonomic information at the
species level. However, no feature is characteristic for the genus. Consequently, the leaf
epidermal features can only play a very limited role in defining the genus.
3.3 Phenetic analyses and their implications
In order to test whether variation in leaf epidermal morphology is correlated with
taxonomic affiliation or is correlated with environmental factors, phenetic analyses were
conducted.
As we have addressed, the results from the UPGMA clustering method show two main
clusters and this grouping is based on a combination of features. Cluster A comprises all the
five species of Calamagrostis s.s. and 16 species of Deyeuxia from all six series, including
three species in ser. Scabrescentes, three in ser. Neglecta, two in ser. Deyeuxia, five in ser.
Tibeticae, two in ser. Tripiliferae, and one in ser. Muticae. Cluster B comprises 11 species of
Deyeuxia from all six series, including one species in ser. Scabrescentes, three in ser.
Neglecta, one in ser. Deyeuxia, two in ser. Tibeticae, two in ser. Tripiliferae, and two in ser.
Muticae. Therefore the results of the phenetic analyses are neither in accordance with the
separation of Calamagrostis s.s. and Deyeuxia nor with the infrageneric classification of Chen
(2001). In Deyeuxia, species in the same series do not tend to cluster together. The leaf
No. 4 MA Hai-Ying et al.: Morphology of leaf epidermis of Calamagrostis s.l. (Poaceae: Pooideae) in China 389
epidermal features provide little taxonomic information above species level.
Nevertheless, it is noteworthy that there are some correlations of certain features.
Thick-walled long cells, frequent short cells and/or prickles, and silicified prickles often occur
together in same species and these species features formed cluster A. Thin-walled long cells,
infrequent or rare short cells or prickles, and unsilicified prickles tend to appear together in
same species and these species formed cluster B.
Cai and Wang (1994) considered that in grasses, prickles and thickened walls of long
cells are adaptations to cold climate. Türpe (1962) and Escalona (1991) both assumed that, in
Deyeuxia, features such as fewer stomata, frequent hairs, and round silica bodies are
correlated with high altitude. Their viewpoints are consistent because high altitude is
associated with cold climate. In our study, species in cluster A include those confined to
Qinghai-Tibet Plateau and four widespread species, C. epigeios, C. pseudophragmites, D.
pyramidalis, and D. neglecta, all of which also extend to highland of Qinghai-Tibet Plateau,
as well as other two species, D. sinelatior and D. tianschanica. Most of them grow at altitude
above 2600 m except the widespread species. For these widespread species, the reason of the
clustering with high altitude species could be that they have developed features adapting to
cold climate so that they have successfully colonized higher altitudes and northern regions. D.
sinelatior and D. tianschanica are two species that grow at lower altitudes, but they are also
distributed in northern areas, which implies that they experience cold climate as well. Most
species in cluster B are distributed in the lowlands of the middle and eastern parts of China,
except for a few ones in the medium mountains of SW China. All species except D. debilis
and D. nivicola grow at altitudes below 2600 m. According to these observations, it seems
that the variation patterns of epidermis in Calamagrostis s.l. have some correlations with
altitude.
In the case of exceptional species, they might have developed different mechanisms to
adapt to the environment, and there might be some environmental factors that have been
neglected. Water, for instance, is another noticeable factor. Stace (1965) found that epidermal
cells are larger on leaves from more humid or shady situations and smaller with drier air and
soil and with higher altitude. Fisher (1939) suggested that sinuous cell walls adds rigidity to
the leaf and prevents from collapse when water is withdrawn. These observations could help
to explain the exceptional case of D. nivicola, and D. debilis. D. nivicola grows at altitudes of
3000–5000 m but is grouped in cluster B. According to Stace (1965), the small size of its
epidermal cells might be a major adaptation mechanism for this species. Although D. debilis
grows at a high altitude of 3350 m, its habitat is very moist. According to Fisher (1939), it is
not necessary to develop thick and sinuous walls to prevent from drought.
There are some widespread species in the genus, but only two of them show infraspecific
variation: D. pyramidalis and C. epigeios. These two are highly polymorphic species in which
numerous hybrids and apomictic forms are found, so we have a preliminary assumption that
the variations in these species are due to the breeding systems in these groups. However, this
cannot be concluded with certainty because plasticity of leaf anatomy has previously been
found in species from other groups of Poaceae (Ramesmar-Fortner et al., 1995).
Unfortunately, the altitude and habitat of some specimens of these two species were not
recorded in present study. This will need further and careful investigation with extensive
sampling on one species. Nevertheless, some useful information and conclusions might be
drawn from present study. Metcalfe (1960) and Cai and Wang (1994) assumed that the
prickles and short cells are homologous. In both C. epigeios and D. pyramidalis, prickles and
short cells seem interchangeable in the same species. Some samples have frequent prickles on
the leaf epidermis, some have frequent short cells, while the others have both prickles and
short cells. No matter how one accounts for the diversity in these two species, whether by
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Vol. 44
breeding system or by environmental factors, the hypothesis that short cells and prickles are
homologous is reasonable, and until now prickles and short cells still seem to have same
function.
4
Conclusions
The present study on leaf epidermal features of Calamagrostis s.l. shows that the
variation of leaf epidermal morphology in the genus can provide some taxonomic information
at the species level but may serve little for infrageneric classification or delimiting the genus.
However, variation in leaf epidermal morphology seems to be correlated with environmental
factors, such as altitude. The variability of leaf epidermal features within Calamagrostis s.l.
illustrates that extensive sampling of species within a genus is needed to fully understand this
large group.
We thank Dr. S. M. Phillips and Dr. S. A. Renvoize of Kew (K) for
constructive comments on early version of the manuscript; Prof. SUN Hang and Mr. WANG
Li-Song of Kunming Institute of Botany, the Chinese Academy of Sciences, for their help in
field work; Ms. ZHANG Yan of KUN and Ms. WANG Mei-Zhi of PE for providing
specimens; Prof. CAI Lian-Bing of Northeast Plateau Institute of Botany, the Chinese
Academy of Sciences, for his valuable advice in experimental techniques; Dr. Hiroyuki
Motomura of Tohoku University from Japan and Dr. CHEN Wen-Li of Institute of Botany,
the Chinese Academy of Sciences for providing some literature. Special thanks go to Dr. Eric
HARRIS of University of California, Berkeley for editing English. We are also very grateful
to two anonymous reviewers for their valuable comments.
Acknowledgements
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禾本科广义拂子茅属的叶表皮形态研究
1, 2
1
马海英
1
彭 华
2
王跃华
(中国科学院昆明植物研究所 昆明 650204)
2
(云南大学生命科学学院 昆明 650091)
摘要 禾本科广义拂子茅属Calamagrostis Adans. s.l.是广布于全球温带和热带亚热带高山的一个大属,
常分为拂子茅属Calamagrostis Adans. s.s.和野青茅属Deyeuxia Beauv.。对国产5种拂子茅属和26种、1变
种野青茅属植物在光镜下进行了叶表皮特征的观察。发现广义拂子茅属植物的叶表皮特征为典型的狐
茅型, 很多结构在种间有丰富的变异式样, 如脉间长细胞形状、大小和细胞壁的厚度与弯曲程度, 短细
胞形状和分布式样, 硅质体形状和分布式样, 气孔形状和分布式样, 以及刺毛形态和分布式样等。在国
产种类中首次发现微乳突结构, 在很多种类中发现刺毛硅质化现象。用UPGMA对15个叶表皮性状进行
分析, 结果分为两大支: 具加厚的长细胞、密集分布的短细胞和(或)刺毛以及刺毛硅质化的种类聚为一
支; 具薄壁的长细胞、较稀疏的短细胞和(或)刺毛以及刺毛不发生硅质化的种类聚为另一支。这种分异
与广义拂子茅属的属下系统相关性不大, 但与种的海拔分布有关。前一支的种类大多生长于高海拔
(2600 m以上)地区, 而后一支的种类则大多生长在低海拔(2600 m以下)地区。
关键词 拂子茅属; 野青茅属; 微形态; 长细胞; 短细胞; 刺毛; 硅质化; 微乳突