Botanical Journal oftke Linnean Socie!J (1988), 97: 159-170. With 14 figures
On a new speci~nen of Pseudoaraucaria major
Fliche (Pinaceae) froiD the Cretaceous
of the Isle of Wight
K. L. ALVIN
Department of Pure and Applied Biology, Imperial College of Science and Technology,
London SW7 2AZ
Received January 1987, accepted for publication April 1987
ALVIN K. L., 1988. On a new specimea of Pse1Uloaraucaria major Fliche (Pinaceae) from.
the Cretaceous of the Isle of Wight. The well-preserved permineralized cone is identified chiefly
on the basis of its large size and large seeds with a relatively thin sclerotesta. The detailed anatomy
conforms to that characteristic of this highly distinctive and probably natural genus of early
Pinaceae. The structure of the scale lends support to the theory that the partially embedded seeds
escaped from the ripe cone by the bending back of the upper part of the scale. The specimen
confirms that the seed testa typically possessed resin cavities as it does in certain living genera. The
relationship of Pseudoaraucaria with other Pinaceae is discussed in the light of the results of a
numerical analysis of 22 cone characters, lending support to the recent suggestion that
Pseudoaraucaria may have occupied a central position in the early evolution of the family.
ADDITIONAL KEY WORDS:-Cluster analysis- conifers- evolution- pines.
CONTENTS
159
160
160
166
166
170
170
Introduction
Methods .
Description
Systematics
Discussion .
Acknowledgements
References.
INTRODUCTION
Pseudoaraucaria Fliche, of which six species are known, represents a genus of
pinaceous seed-cones of Cretaceous age. It possesses a highly characteristic
combination of features not found together in the cone of any living genus and
two unique characters, namely, a prominent ridge of scale tissue separating the
two seeds which are therefore almost embedded in the scale base and an
extensive pad of sterile tissue at the chalaza! end of the seed. Almost certainly it
represents an extinct natural genus. Recently the suggestion has been put
forward that it may occupy a key position in the early evolution of the family
(Miller, 1985).
159
0024--4074{88/060159+ 12 $03.00/0
© 1988 The Linnean Society of London
160
K. L. ALVIN
The specimen described is unfortunately only imprecisely localized as
“Luccombe Chine, Isle of Wight”. However, the matrix, a greenish grit,
adhering to the permineralized cone strongly resembles that typical of the
Sandrock outcropping at the mouth of Luccombe Chine and which contains
abundant plant remains, chiefly permineralized wood. Some fragments of wood
are in fact preserved in the matrix adhering to the cone.
The specimen is well preserved in calcium carbonate with some local
deposition of iron pyrites. Its surface had obviously been severely abraded
before permineralization. It is identified as Pseudoaraucaria major Fliche ( 1896), a
species originally described from Les Islettes (Meuse), France. A brief emended
diagnosis of the species was published by Alvin (1957a) on the basis of
observations on two isolated cone-scales which was all that apparently remained
of the type material in the collection of the h o l e nationale supkrieure de
Gtologie appliqute, Nancy.
The new specimen is identified chiefly on the basis of its large size and
characteristic seed structure.
METHODS
The specimen was cut transversely and longitudinally and series of cellulose
acetate peel sections taken in transverse, radial longitudinal and tangential
longitudinal planes. Etching was carried out in 5% hydrochloric acid.
DESCRIPTION
Apart from the adhering matrix, the surface of the cone is smooth and
covered with abraded scales; no scale end is preserved.
The axis is about 10 mm in diameter and contains a central pith about 4 mm
in diameter surrounded by a somewhat highly dissected vascular cylinder and
a wide cortex. The pith is composed of thick-walled parenchyma cells,
isodiametric or slightly elongated longitudinally, but of varied size. The cells
generally have a lining of a dark substance so that the tissue as a whole has a
dark appearance.
The vascular cylinder is rather inconspicuous and considerably dissected with
gaps between the vascular bundles of nearly the same tangential width as the
bundles themselves (Fig. 1). Bundles are made up of mainly radially seriated
xylem elements and poorly preserved phloem. Tracheids are 15-25 pm in
diameter but somewhat larger and thinner walled towards the pith (primary
xylem). No resin canals are present in the vascular tissues.
The cortex is massive, demarcated only indistinctly from the closely arranged
scale bases. It consists of very thick-walled cells of varied size and shape, the cells
tending to increase in size and to become more radially elongated towards the
outside. The cortical resin canals are 200-400 pm in diameter and run
longitudinally, branching in association with the scale bases so that each scale
receives branches from two axial canals (Fig. 1).
The seed-scale complex consists of a relatively small bract subtending a
massive ovuliferous scale, the latter being clearly differentiated into a lower,
horizontal seed-bearing portion and a distal, upturned portion of unknown
length. The bract remains united to the ovuliferous scale to about half-way
CRETACEOUS PSEUDOARAUCARIA
161
I mm
Figure 1. Transverse section of the cone-axis of Pseudoaruucuriu major showing xylem (solid black)
and resin canal system. Slide BGS PF 5815.
along the length of the seeds. The lower portion of the ovuliferous scale with its
two seeds is of the shape and structure typical for the genus (Alvin, 1957a;
Miller, 1977). It rapidly expands from a relatively small rhomboidal attachment
to about 10 mm in width at the junction with the distal portion of the scale. The
interseminal ridge is a prominent feature throughout most of the length of the
seeds (Figs 2, 5), but towards the chalazal end it attenuates markedly so that the
chalazal cushions of the two seeds eventually come into contact (Fig. 6).
The vascular system supplying the ovuliferous scale and bract is similar to
that in the other known species of Pseudoaraucaria. Traces run into the scale
horizontally (Fig. l ) , the two ovuliferous scale traces uniting to form a small
semicircular strand (Fig. 3) which tends to retain for some time a ray-like
division into two portions before uniting completely and then flattening in the
scale base to form a conspicuous band of xylem (Fig. 4). The bract trace
remains entirely separate from the ovuliferous scale strands throughout and
terminates about where the bract becomes free.
Apart from a little thin-walled parenchyma beneath the scale trace
(appearing dark in Fig. 3) the extreme basal part of the scale consists of a
uniform, thick-walled tissue similar to that of the cone cortex. The cell walls of
this tissue always appear to consist of two layers: an outer, pale yellowish or
colourless layer and a thicker inner, brownish layer (stippled in Fig. 7B); the
lumen is filled partially or completely with a dark substance. Pits have not been
observed. This tissue is retained in the wing-like portions of the scale base
(Fig. 6) and also adaxially throughout most of the length of the seeds, but gives
way rapidly to a predominently thin walled parenchyma at the level of the seed
bases (Figs 5, 11). Abaxially to the ribbon-shaped xylem strand, the tissues are
differentiated into two or three zones, probably resembling the tissues described
in Pseudoaraucaria loppineti (Alvin, 1957a). The outermost layer (Figs 7A, 9) is
162
K. L. ALVIN
Figures 2-4. Pseudoaraucaria major. Part of the tengential LS through the cone showing portions of
scale bases and embedded seeds. Scale bar = 1 mm. Slide BGS PF 5821. Fig. 3. Oblique tangential
section through the ovuliferous scale trace (above) and bract trace (below) in the outer cortex of the
cone axis; dark tissue below the ovuliferous scale trace is thin-walled parenchyma. Scale
bar = 0.5 mm. Slide BGS PF 5817. Fig. 4. Vertical section through the outer region of the scale
base showing bract (b) in cross-section and tissues of the ovuliferous scale; x = xylem band. Scale
bar = 0.5 mm. Slide BGS PF 5823.
difficult to interpret: it appears at first sight to consist of relatively thin-walled
cells with dark cell contents often of rather irregular form. Towards the xylem
this grades into a tissue of somewhat similar appearance but in which the pale
layer outside the cell contents resembles a thick inner-wall layer (Fig. 9).
Throughout this abaxial tissue the cells are strongly elongated longitudinally,
but are square-ended rather than tapered. It seems likely that the whole may
consist of a thick-walled tissue but in which the inner-wall layer may vary in
structure and composition. Perhaps in the outermost region the cells are
gelatinous, as in the tissue in a similar position in Cedrus, but become less so
towards the xylem band. Immediately beneath the xylem there is a zone of
dark, thin-walled parenchyma (Fig. 4).
This organization of the abaxial tissues is retained to just beyond the chalaza1
end of the seeds where the scale bends abruptly upwards. At this level the xylem
band breaks up into small strands of which there are eventually about 40. Resin
canals which, in the basal part of the scale lie entirely adaxial to the xylem, now
extend to the abaxial side. I n the upturned part of the scale the tissues are at
first more or less stratified, with bands of fibres adaxially and abaxially and two
or three rows of resin canals (Fig. 8), but more distally they become less so with
CRETACEOUS PSEUDOARAUCARIA
Figures 5 and 6. Pseudoaraucaria major. Part of a tangential section through the cone showing a
vertical section through the middle region of the horizontal part of the scale; tr = ribs of testa. Scale
bar = I mrn. Slide BGS PF 5823. Fig. 6. Vertical section through the scale base (tangential to
cone), passing through the chalaza1 cushions of the seeds; st = seed trace; w = wing-like lateral
portion of the scale. Scale bar = 1 rnrn. Slide BGS PF 5827.
163
164
K.L. ALVIN
Figure 7. Pseudoaraucaria major. A. Transverse section of abaxial tissue at and just below the bend in
the scale base. Slide BGS PF 5815. B. Transverse section of tvpical thick-walled tissue of the cone
cortex and the scale base. Slide BGS PF 5824. C. Chalaza1 tissue showing thin, pitted walls. Slide
BGS PF 5818.
Figures 8-10. Pseudoaraucaria major. Fig. 8. Transvene section through the scale near the bottom of
the upturned portion. Scale bar = I mm. Slide BGS PF 5815.Fig. 9.Transverse section of abaxial
tissue near the bend in the scale. Scale bar = 0.1 mm. Slide BGS PF 5815. Fig. 10. Transverse
section through part of the more distal portion of the scale. Scale bar = 0.5 mm. Slide
BGS PF 5816.
CRETACEOUS PSEUDOARAUCARIA
165
Figures 11-13. Pseudoaraucaria major. Fig. 11. Tangential section through the cone passing obliquely
through the base of a scale, showing the attenuated interseminal ridge and the chalazal tissue of the
seeds containing resin cavities. Scale bar = 0.5 mm. Slide BGS PF 5823. Fig. 12. Part of testa in
longitudinal section; thick-walled scale tissue below. mm = megaspore membrane; rc = resin
cavity. Scale bar = 0.2 mm. Slide BGS PF 5817. Fig. 13. Chalaza1 tissue in longitudinal section
showing pits. Scale bar = 0.2 mm. Slide BGS PF 5818.
scattered resin canals and groups of fibres in a well-preserved parenchymatous
ground tissue. Vascular strands are always in a single central row (Fig. 10).
The seeds are larger than in other species of Pseudoaraucaria, the seed cavity
~ mm. The testa consists of three layers: an
being typically about 6 . 0 3.5
outermost layer, mainly of two or three layers of thin-walled cells, a middle
layer (sclerotesta) of stone cells and an inner layer, the cells of which are not
well-preserved (Fig. 12). The outermost layer is continuous with the chalazal
cushion which consists of thin-walled cells of irregular shape and size with
conspicuously pitted walls (Figs 7C, 13). This layer also contains resin cavities
most of which lie in shallow depressions in the sclerotesta a t the chalazal end
(Fig. 1 I ) , although a few smaller ones are occasionally present elsewhere
(Fig. 12). Longitudinally running ribs are a conspicuous feature of the
outermost testa1 layer extending from the chalazal cushion along either side of
the seed to the micropylar end (Fig. 5); they are unequal in size, the outer one
(lying towards the outer edge of the scale) being larger and with a better
developed core of thick-walled cells than the inner one (lying towards the top of
the interseminal ridge). The thick-walled cells within the ribs are different from
those of the sclerotesta; they are polygonal in shape with a wall of paler, less
dense appearance. The sclerotesta is remarkably thin for the size of the seed,
being only about 0.15-0.2 mm thick except at the chalazal end where it is
K. L. ALVIN
I66
thicker. The stone-cells of the sclerotesta are rather irregular in shape with very
thick walls, the substance of which is darker than that of other thick-walled cells
(Fig. 12). The seed is supplied with a rudimentary vascular bundle. No distinct
vascular elements have been observed, but the sheath of thick-walled cells
passing through the chalazal cushion is a conspicuous feature (Fig. 6).
The seed contents are either completely missing or else only very poorly
preserved. The nucellar beak is often recognizable at the micropylar end and the
megaspore membrane is usually present (Fig. 12). One seed has been seen
containing an ill defined embryo surrounded by ‘endosperm’ tissue, but no
details of structure are discernible.
SYSTEMATICS
Pseudoaraucaria major Fliche emend. K. L. Alvin
pseudoaraucaria major Fliche, Bulletin de la Socit!tt! scientijique de Nancy, 14:
191, pl. VII, fig. 1 (1896).
SYNONYM:
SPECIFIC DIAGNOSIS: Ovulate cone ellipsoidal-cylindrical,
up to
75 x 50 mm (or more); axis 12 mm in diameter, surrounded by contiguous,
spirally arranged ovuliferous scales and their subtending bracts; pith uniform,
parenchymatous; vascular cylinder 0.3-0.5 mm thick, of 17-20 bundles; xylem
lacking resin canals; cortex of thick-walled cells, with ring of 21-23 large resin
canals; bract trace small, departing from bottom of gap in axial cylinder;
ovuliferous scale traces two, one from each side of the gap, uniting to form a
semicircular strand; bract about 2.5 mm wide, united to scale base a t first, then
extending free for about 8 mm; ovuliferous scale 25 mm (or more) long, up to
30 mm wide; basal part of scale horizontal, rhomboidal in section, increasing
from 3 mm wide and 3 mm high at base to 8 x 20 mm at the chalazal end of the
seeds; abaxial tissues strongly stratified in basal part of the scale, adaxial mostly
uniform and resembling cortical tissue, but becoming thin-walled
parenchymatous distally at level of seed attachment; upturned part of scale
more uniform with about 40 small bundles; resin canals of ovuliferous scale and
bract supplied from two cortical canals, distributed entirely adaxially in scale
base, becoming both adaxial and abaxial in upper part; seed winged, with
massive pad of thin-walled pitted tissue between seed and wing; seed body
(including chalazal pad) 12 mm long, 4 mm wide; sclerotesta mostly thin,
0.15-0.2 mm, thicker a t base; resin cavities in outer layer of testa, especially at
base between pad and sclerotesta.
EMENDED
HOLOTYPE: Specimens in Ecole nationale suptrieure de Gtologie appliqute,
Nancy, France.
Specimen No. GSM 77239, British Geological
Survey, Keyworth, Nottinghamshire.
NEW SPECIMEN DESCRIBED HERE:
OCCURRENCE:
Albian, Les Islettes (Meuse), France; Aptian (?), Isle of Wight,
England.
DISCUSSION
The specimen described is identified as Pseudoaraucaria major because it agrees
closely in size and structure with the type material as described by Fliche
CRETACEOUS PSEUDOARAUCARIA
167
(1896). The scales representing part of the type material examined by Alvin
(1957a) showed evidence of a conspicuous strand of fibrous tissue running below
the scale trace. This feature is not so obvious in the specimen from the Isle of
Wight. Thick-walled cells similar to those of the cone cortex and the scale base
are present in this position but are apparently not so sharply differentiated from
the adjacent thin-walled tissue as they seemed to be in the French material. In
my view, this distinction does not provide sufficient grounds for erecting a new
species for the English cone. The French material is probably somewhat
younger (Albian) in age (Louvel, 1960).
Pseudoaraucaria major is distinguished from the five other known species chiefly
by its larger size and the comparatively thin slerotesta. The specimen is one of
the best preserved of any species and elucidates certain structural features which
have hitherto been unclear. The tissue of the massive chalazal cushion is
extremely well preserved in spite of being thin-walled. The function of this tissue
is obscure; its anatomy is perhaps suggestive of a storage function. Food or water
storage could have been of importance in seed development. Its shrinkage on
drying out at cone dehiscence could have facilitated the escape of the seeds.
Although Alvin (1957a, b; 1960) expressed doubt about the occurrence of
true resin cavities in the seed of Pseudoaraucaria, because there seemed to be a
lack of any remains of resinous material in the seed-coat cavities he observed,
the cavities in P . major are not only very well-defined but often contain a
yellowish substance, although this is usually less conspicuous than in the
ordinary resin canals. The presence of resin cavities in the testa is likely to be a
generic character.
The mode of dispersal of the seed in Pseudoaraucaria remains somewhat
uncertain. The strong development of the seed wing, which seems characteristic
of the genus, implies that the seed escaped by some means from the cone. This
could have happened in the same way as in Cedrus, Abies or Pseudolarix among
living genera, namely by the scales separating from the cone-axis. However, no
specimen of any species gives direct evidence that this happened. Moreover, the
relatively strong scale trace and the thick-walled nature of the scale tissue
continuous with that of the cone cortex would seem to rule out the shedding of
the scales at maturity. Alvin (1957b), on the basis largely of the occurrence of a
number of specimens of P . heeri in which the upper parts of the scales were
completely missing and from which some of the seeds had escaped, suggested
alternatively that the breaking off of the upper part of the scale might have been
the method by which seed escape occurred. The rather abrupt change in the
structure of the adaxial scale tissue at the chalazal end of the seeds, and the
similarly abrupt break-up of the strong xylem band into a large number of small
strands at about the same point in P . major, may lend some support to this idea.
Miller & Robinson (1975), on the basis of a specimen of P . arnoldii with intact
scales but lacking seeds, concluded that its seeds escaped by the bending
outwards of the upper part of the scale as in most living Pinaceae. I am inclined
to agree that this seems the most likely hypothesis. The strong continuity of the
abaxial tissues of the scale in P . major makes it unlikely that the upper part of
the scale could have broken off completely. If, as I suspect, the mechanical cells
abaxial to the vascular band at the bend in the scale were of a gelatinous
nature, the shrinkage on drying of this tissue could have produced enough
bending outwards of the upper part to allow seed escape. It is noteworthy that
168
K. L. ALVIN
in shed scales of Cedrus, where the gelatinous nature of the abaxial fibrous tissue
is conspicuous, the upper part of the scale is virtually in line with the lower part,
whereas in the cone before dehiscence it is more or less at right angles. In the
cones of P. heeri (Alvin, 1957b), which had lost the upper parts of the scales,
these had probably broken off after dehiscence by abrasion.
The evolutionary relationship of Pseudoaraucaria with other Pinaceae is obscure.
Pinaceous remains are common in the Cretaceous and numerous species of seedcones have been described. However, their classification is difficult (Alvin, 1953,
1960; Miller, 1977, 1985). Pityostrobus Nathorst, a genus into which many
diverse species have been classified is almost certainly an artificial assemblage.
Many of the species resemble living genera in most of their characters but are
always distinguished by certain significant features. Those with a general
resemblance to Pinus are especially common. The assemblage may represent
several natural genera of actively evolving early Pinaceae some descendants of
which may survive as living genera. Pseudoaraucaria, on the other hand, almost
certainly represents a natural genus. The six known species share many features
and include some that are unique to the genus. Miller (1985), in describing a
new species of Pityostrobus ( P .pubescens) which has a number of Pseudoaraucaria
characters as well as some important features in common with certain living
genera (other than Pinus), suggested that Pseudoaraucaria may have been
involved in the evolution of modern genera with Pit_yostrobus pubescens
representing an intermediate.
An analysis of extant genera of Pinaceae (except Cathaya), including also
Pseudoaraucaria, based on 22 cone characters, has been carried out using cluster
analysis. The characters used and the states recognized are shown in Table 1
and their distribution among genera in Table 2. The characters were selected
for their high degree of constancy in genera. Where some variation occurs, the
TABLE
1. List of cone characters and recognized states
1. Vascular cylinder of cone axis little dissected ( I ) , highly dissected (2)
2. Resin canals in wood present ( I ) , absent (2)
3. Umbo present at scale tip ( I ) , absent (2)
4. Tip of scale straight ( I ) , reflexed (2)
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
Scale apex obtuse or rounded ( I ) , strongly pointed (2)
Scale straight ( I ) , distinctly bent (2)
Interseminal ridge weak ( I ) , stronger (2), massive (3)
Scale elongated ( I ) , about as long as broad (2), broader than long (3)
Scale thick ( I ) , thin (2)
Scales persistent ( I ) , falling at maturity (2)
Bract short and simple ( I ) , longer, apex sometimes cleft (2), very long, usually protuding, tridentate (3)
Vascular trace to scale cylindrical with separate bract trace ( I ) , semicircular with separate bract trace
(2), cylindrical with combined bract trace (3)
Vascular bundles in scale typically with straight cambium ( I ) , with curved cambium (2)
Mechanical tissue of scale base well developed ( l ) , modified (2)
Mechanical tissue at scale base fibrous ( I ) , highly gelatinous (2)
Seed trace present ( I ) , absent (2)
Resin canals in scale base abaxial ( I ) , both sides (2), adaxial (3)
Attachment ofseed wing by upper surface ofseed ( I ) , by end and both sides (2), by end and one side (3)
Ribs in testa prominent ( I ) , indistinct or absent (2)
Massive chalaza1 cushion absent ( I ) , present (2)
Resin cavities in seed absent ( I ) , present (2)
Sclerotesta thick ( I ) , thin (2)
CRETACEOUS PSEUDOARAUCARIA
169
0.5
0.0
.g
~
"'~ ~"'
-~
'-
"' .g
~
~
ct
~
"
.Q
~
~
~
g-
5
.....
"'
.g
.g
ct"'
..,<:>
~
<:>
-~
C)
::.
~
·~
<:>
-.J
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--.
c:
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iS"':
c:
.Q
.Q
.Q
.Q
~
~
~
~
::.
~ ~~
"'::. "'::.
Figure 14. Dendrogram showing results of Cluster Analysis based on 22 cone and seed characters.
Vertical scale is the complement of the similarity coefficient.
most usual state was taken as representative. Character states were scored so
that the assumed primitive or relatively simple condition was low, the derived,
or more specialized, high. For some characters such assessment is difficult and
can only be guessed at. The results, using Gower's Distance Matrix, including
negative matches (Sokal & Rohlf, 1969), are given in Fig. 14. Two features are
striking: firstly, Pseudoaraucaria is linked with the living genera at a very high
level, suggesting a relatively primitive and basic position; secondly, the other
genera form two clusters corresponding to the two sections of the family,
2. Distribution of cone character states in living genera of Pinaceae and Pseudoaraucaria
Abies
Cedrus
Keteleeria
Larix
Picea
Pinus ( Haploxylon)
Pinus ( Diploxylon)
Pseudolarix
Pseudotsuga
Tsuga
Pseudoaraucaria
P
TABLE
2
3
4
5
6
7
8
9
2
2
2
2
2
I
I
I
I
I
I
2
I
I
I
I
I
I
I
I
I
I
I
2
2
I
I
I
I
I
I
I
I
I
I
I
3
3
2
2
I
I
I
I
I
I
2
2
2
I
I
I
I
I
I
I
2
3
2
I
I
I
I
I
I
I
I
I
2
2
I
I
I
2
2
2
2
2
2
I
I
2
2
2
I
2
2
2
I
I
I
2
2
2
2
I
I
I
I
Character
10 II 12 13
2
2
I
I
I
I
I
2
I
I
I
2
2
I
I
I
2
2
I
I
I
I
2
2
2
3
2
3
2
2
2
I
2
I
I
3
I
3
3
14 15
16 17
I
I
2
2
I
I
I
I
2
2
I
I
I
I
I
I
2
2
I
I
I
I
I
I
I
I
I
2
2
I
2
2
2
2
3
2
2
3
3
2
I
I
I
2
2
2
2
I
2
2
3
3
3
I
I
18 19 20 21
2
3
2
3
2
2
2
2
2
2
2
2
I
I
I
I
I
I
I
I
I
I
I
2
I
I
2
22
2
2
2
2
2
I
I
I
I
I
I
I
I
2
2
2
I
I
2
I
2
I
170
K. L. ALVIN
Abieteae (Abies, Cedrus, Keteleeria, Pseudolarix and Tsuga) and Pineae (Pinus,
Picea, Larix and Pseudolsuga) which were recognized by Jeffrey ( 1905) largely on
the basis of certain secondary wood characters, chiefly the presence or absence
of resin canals. That Pinus links with the rest of the Pinaceae at high level
supports the fossil evidence that this genus is relatively primitive. The results are
consistent with the idea that Pseudoaraucaria is a primitive genus to which both
Pineae and Abieteae are related and which may have occupied a basic position
in the evolution of the family.
ACKNOWLEDGEMENTS
I am grateful to Dr D. H. Dalby for carrying out the numerical analysis and
assisting in the interpretation of the results. I also wish to thank M r Sinclair
Stammers for photographic assistance and the Director of the British Geological
Survey for the loan of the material.
REFERENCES
ALVIN, K. L., 1953. Three abietaceous cones from the Wealden of Belgium. Mkmoires de I'lnstitut royal des
Sciences naturelles de Belgique, no. 125.
ALVIN, K. L., 1957a. On the two cones Pseudoaraucaria heeri (Coemans) nov. comb. and Pityostrobus uillerotenris
nov. sp. from the Wealden of Belgium. Mkmoires de /'Instilut royal des Sciences naturelles de Belgique, no. 135.
ALVIN, K. L., 1957b. On Pseudoaraucaria Fliche emend., a genus offossil pinaceous cones. Annals of Botany, 21:
33-5 1.
ALVIN, K. L., 1960. Further conifers of the Pinaceae from the Wealden Formation of Belgium. Mkmoires de
l'lnstitut royal des Sciences naturelles de Belgique, no. 146.
FLICHE, P., 1986. Etude sur la flore fossile de 1'Argonne (Albien-Cenomanien).Bulletin de la SociktdscientiJigue de
Nancy, 14: 114-306.
JEFFREY, E. C., 1905. Comparative anatomy and phylogeny of the Coniferales. Part 11: The Abietineae.
Memoirs of the Boston Society of Natural History, 4 : 1-37.
LOUVEL, C., 1960. Contribution B I'ktude de Pilyostrobus oblongus (Fliche sp.) appareil femelle d'un conifere
Albien de I'Argonne. Mknoires de la Socikfkgkologique de France, 39 (90).
MILLER, C. N., 1977. Mesozoic conifers. Botanical Review, 43: 217-280.
MILLER, C. N., 1985. Pibostrobuspubescens, a new species of pinaceous cones from the Late Cretaceous of New
Jersey. American journal of Botany, 72: 520-529.
MILLER, C. N. & ROBISON, C. R., 1975. Two new species of structurally preserved pinaceous cones from
the Late Cretaceous of Martha's Vineyard Island, Massachusetts. Journal of Paleontology, 49: 138-150.
SOKAL, R. R. & ROHLF, F. J., 1969. Biometry. San Francisco: Freeman.