Carpolithus conicus (Cycadales?) Lindley and Hutton.
The original specimen figured by Lindley and Hutton[1377] from the Coralline Oolite of Malton, Yorkshire, as Carpolithes conica and now in the Manchester Museum, is represented in fig. 584. A second ‘species,’ Carpolithus Bucklandi Lind. and Hutt. ex Will. MS.[1378], from the same locality is no doubt specifically identical with C. conicus. The seeds are conical, broadly truncate at one end, presumably the base, and tapered to a blunt apex; the broad end is characterised by the presence of three ridges or in some specimens by a single median ridge illustrating an oscillation between the radiospermic and platyspermic form similar to that in Ginkgo biloba. As usually obtained the seeds are probably nucules or casts showing the surface-features of the inner wall of the sclerotesta, the sarcotesta having been destroyed before fossilisation: the irregular marginal teeth at the truncate end suggest casts of vascular bundles in the integument. The scattered tubercles on the sides of some of the seeds (fig. 584, a) are probably casts of holes in the shell bored by insects and comparable with those occasionally preserved on the casts of Trigonocarpus. A specimen in the Malton Museum shown in fig. 585 which may be an example of this species illustrates the occurrence of an internal cast enclosed by the remains of a thick testa. These Jurassic casts resemble the seeds of Macrozamia Fraseri, but it is impossible to determine their systematic position with confidence.
Carpolithus sp. (Cycadales?) Seward.
An unusually well preserved specimen from the Wealden beds of the Sussex coast described under this name in 1895[1379] consists of a kernel and mould, 1·8 × 1·1 cm. The mould from which the kernel is readily removed is lined with a thin structure representing part of the testa and between this and the surrounding rock is a layer of coal. On the surface of the kernel, probably the cast of the seed-cavity, a reticulum of narrow grooves indicates the course of the vascular bundles over the surface of the nucellus.
Carpolithus (Cycadales?) Pomelii (Saporta).
The specimen from the Upper Corallian of Châteauroux (Indre) on which this species was founded by Saporta[1380] under the name Cycadeospermum Pomelii is a large ovate cast, 5·5 cm. long and 3·5 cm. broad, closely resembling some of the larger recent Cycadean seeds: it cannot be accepted as a true record of the group without reservation.
Saporta describes other species of Cycadeospermum but none of them are of any real importance from a botanical point of view: the same remark applies to the seeds referred by Fontaine[1381] from Potomac beds to the same genus, also to many other recorded examples of seeds that afford no decisive evidence of affinity.
Some specimens described by Compter[1382] from the Lettenkohle of Apolda (Thuringia) as Cycadean fruits—too imperfect to be determined with accuracy—furnish an additional illustration of the slender foundation on which many of the records of supposed Cycadean reproductive organs are based.
CYCADOSPADIX. Schimper.
This name was proposed by Schimper[1383] for some French Jurassic fossils, described by Pomel[1384] as Crossozamia Hennocquei and C. Moraeana, on the ground that they bear a close resemblance to the megasporophylls of Cycas. Their occasional association with Otozamites fronds suggested a reference to the same parent-plant, but such data as we have point to Otozamites fronds having been borne by plants with the Williamsonia type of flower. Schenk[1385], who figured a specimen of Cycadospadix from France as the inflorescence of a Cycad, expresses the more probable opinion that it belonged to a plant with Cycadites fronds. A Permian species described by Renault as Cycadospadix Milleryensis is now transferred to the genus Strobilites[1386].
Cycadospadix Pasinianus Zigno.
This species, first described from Jurassic strata in Northern Italy[1387], is recorded also from the Kimmeridgian of France[1388] and Scotland[1389]. Zigno’s figures give a fairly accurate representation of the type-specimens in the Padua Museum. The megasporophylls, almost identical in shape with those of some recent species of Cycas (figs. 381; 392, A–C), consist of a broadly lanceolate or triangular limb with deeply laciniate sides terminating a pedicel, or the distal expansion may be preserved without the stalk from which it was no doubt easily detached as in certain recent Cycads (cf. fig. 392, A). In the specimen from Scotland there are no clear indications of veins in the lamina, which may have been woolly as in Cycas. In some of the specimens figured by Saporta[1390] and now in the École des Mines, Paris, the stalk is absent, but in pedicellate examples scars occur on the sides of the narrow axis and casts of seeds are found in the same beds. A good example of Cycadospadix Hennocquei is figured by Saporta from a drawing supplied by Schimper showing two seed-scars near the base of the lamina: the same specimen, as figured by Saporta and Marion[1391], bears a seed, but this is presumably a partial restoration. The occurrence of Cycadites rectangularis Brauns at Hettange in association with Cycadospadix strengthens the conclusion, based on the form of the megasporophylls, that some of the Jurassic Cycads bore megasporophylls very similar to those of existing species of Cycas.
Cycadospadix integer Nathorst.
This Rhaetic species from the south of Sweden[1392] was instituted for an imperfect broadly lanceolate lamina recalling the distal end of the megasporophyll of a Cycas: the discovery of a more complete example[1393] justifies Nathorst’s use of the name Cycadospadix, though without further evidence one hesitates to regard the species as a thoroughly trustworthy record of a Cycadean fertile leaf. The species is characterised by the entire margin of the broad and relatively short and thick terminal limb borne on a broad stalk with alternate lateral projections presumably marking the position of the seeds.
These species of Cycadospadix are particularly interesting as evidence—though not amounting to demonstration—of the production by some Jurassic and Rhaetic plants of fertile leaves agreeing closely with those of Cycas. It would seem from the abundance of Bennettitalean flowers and the very scanty remains of fertile leaves or cones like those of modern Cycads that the existing type was exceptional in Mesozoic floras.
BEANIA. Carruthers.
Beania gracilis Carruthers.
The generic name Beania[1394] was given to a branched fertile shoot (fig. 586) from the Middle Jurassic beds at Gristhorpe, Yorkshire, characterised by loosely disposed sporophylls bearing two sessile seeds: each sporophyll is given off at a wide angle from a fairly stout axis and the seeds are borne on the adaxial side of a peltate distal expansion. Carruthers compared the type-species with a cone of Zamia with which it agrees in the general plan of construction but differs in the more open habit and in the longer and more slender seed-bearing pedicels. The same type of shoot was figured by Lindley and Hutton[1395] as Sphaereda paradoxa. Beania is generally regarded as a Cycadean reproductive shoot, but there is no doubt that the majority of Jurassic Cycadophyta possessed flowers of the Bennettites types, and it is clear that Beania differs considerably from Bennettites and Williamsonia. Another suggestion is that Beania may belong to some member of the Ginkgoales[1396]: though very different from the normal ovuliferous shoot of a Ginkgo, it resembles some abnormal forms (e.g. fig. 631, D) in which the ovules occur on elongated pedicels, but they are borne singly and the micropyle is directed outwards, while in Beania the ovules are attached in pairs to the inner face of a distal expansion. There is no conclusive evidence in support of either interpretation, though the general agreement between the Jurassic type and the cones of recent Cycads would seem to favour the inclusion of Beania among the Cycadophyta.
A specimen described by Nathorst[1397] from Upper Jurassic rocks in the North of Scotland as Beania Carruthersi closely resembles the type-species, differing chiefly in its smaller size and in the rather closer arrangement of the sporophylls. The seed-like bodies borne in pairs on the adaxial side of the terminally expanded pedicels are covered with small granulations which Nathorst thinks may be clusters of microspores, the apparent seeds being ‘antherangia.’ The granulations are, however, very similar to those on the larger detached seed-like bodies originally described by Nathorst from Rhaetic beds in Sweden as Antherangiopsis rediviva[1398]: subsequent examination of that species demonstrated that the granulations are due to the presence of resinous bodies in the tissues of true seeds[1399], and it is not improbable that a similar interpretation may hold for the surface-features in the supposed male organs of Beania Carruthersi. Pending further evidence it may be suggested that Beania Carruthersi is like B. gracilis a seed-bearing shoot. The Rhaetic specimens described by Nathorst as Stenorrachis scanicus[1400] are similar in habit to Beania but differ in the forking of the sporophylls (fig. 656) and in the absence of any terminal swelling on which the seeds are borne: Nathorst considers that Stenorrachis may be the female organ of a Nilssonia and it is not improbable that that genus and Beania are closely allied types. We have no definite information with regard to the reproductive organs of the Nilssoniales: the closer resemblance which their fronds bear in the structure of the epidermal cells to those of recent Cycads is consistent with the view that their fertile shoots were also more like those of existing types. It is, however, still an unsettled point whether Beania is more closely allied to the Cycadophyta or to the Ginkgoales, but the balance of opinion is in favour of the former alliance.
Zamiostrobus. Endlicher.
Cycadeostrobus. Carruthers.
Though instituted by Endlicher[1401] for a cone figured by Lindley and Hutton as Zamia macrocephala[1402] which is almost certainly Abietineous and has no claim to be included in the Cycadales, the genus Zamiostrobus has been adopted by many authors for Cycadean ovulate cones, not only such as are believed to be closely allied to those of Zamia but for Cycadean cones generally. Carruthers[1403] suggested Cycadeostrobus as a more suitable name on the ground that it is less limited in its implication of affinity; but, as Fliche points out, Endlicher’s generic name has been widely adopted in a comprehensive sense as standing for Cycadean megastrobili, excluding the supposed Cycas-like megasporophylls, included under Cycadospadix.
Many of the specimens described as species of Zamiostrobus are of little or no value as records of Cycadean plants, e.g. Zamiostrobus orientalis Heer[1404] from the Jurassic beds of Amurland. A Lower Cretaceous (Albian) species described by Fliche[1405] as Zamiostrobus Loppineti, though not entirely satisfactory, is more likely to belong to the Cycadales. The type-specimen is an elliptical strobilus, 5·5 cm. × 3·2 cm., consisting of an axis bearing at right-angles numerous small, contiguous, peltate megasporophylls each with two small seeds on the lower surface. The figures given by Fliche are, however, not convincing. An examination of specimens in the British Museum, from Wealden and Jurassic rocks, described by Carruthers as species of Cycadeostrobus, convinced me that several are undoubtedly Araucarian cones[1406]. Solms-Laubach[1407] called attention to the Araucarian appearance of Cycadeostrobus Brunonis, a cone from an unknown locality, and this with other species, e.g. C. elegans, C. sphaericus, C. truncatus, etc., may safely be referred to Araucarites. The specimen figured by Lindley and Hutton[1408] as Zamia crassa from the Inferior Oolite of Towcester (Northamptonshire) affords no satisfactory evidence of Cycadean affinity. The Lower Cretaceous Bohemian specimens described by Corda[1409] and Velenovský[1410] as Microzamia gibba should not be included in a genus implying Cycadean affinity: though Velenovský states that the megasporophylls bear a pair of seeds his illustrations do not afford any satisfactory evidence of this Cycadean character. Similarly the fossil regarded by Carruthers[1411] as probably a male flower of Bucklandia is almost certainly an Araucarian cone. A small cone from the Lower Miocene of Armissan (Aude) named by Schimper Zamiostrobus Saportana and figured by Saporta and Marion[1412] may, as Solms-Laubach says, be Cycadean, but we have no information with regard to the internal structure or as to the presence or position of the seeds.
Androstrobus. Schimper.
Schimper[1413] instituted this genus for ‘amenta, cycadeacea antherifera, cylindrica, e squamis imbricatis, latere postico antheras sessiles ferentibus efformata.’ It may conveniently be applied to fossils which resemble the male cones of recent Cycads sufficiently to justify the use of a name implying relationship. As so defined, Androstrobus is used in a more restricted sense than the word suggests, just as Masculostrobus[1414] has been employed for fossils that are believed to be the corresponding organs of Conifers. Among the few species assigned to Schimper’s genus reference may be made to A. Balduini Sap., originally named by Schimper A. zamioides, from the Upper Bathonian of Etrochy, and A. Guerangeri (Brongn.), another French type[1415]. Heer’s species A. sibirica[1416] of Jurassic age is represented by a slender axis bearing numerous appendages which in surface-view have the form of polygonal discs: there are no indications of microsporangia and the evidence of Cycadean affinity is far from convincing. Nathorst’s Rhaetic species A. borealis[1417] is no more satisfactory as a record of a Cycadean strobilus. A fossil from the Lower Cretaceous of Bohemia described as Zamites familiaris and regarded by Corda[1418] and Carruthers[1419] as a male flower of a Cycad though not above suspicion may be included in Androstrobus.
Under the name Fričia nobilis Velenovský[1420] described some cones from the Lower Cretaceous plant-beds of Bohemia which he regards as male strobili of some Cycadean plant: the cone, as shown in Velenovský’s restoration, is 10 cm. long and 5 cm. in diameter; it bears a close superficial resemblance to a large cone of Zamia and consists of a stout axis bearing contiguous peltate, hexagonal, scales gradually contracted towards the proximal end, similar to those of Androstrobus. The evidence on which this species is identified as a male cone rests on the occurrence of numerous pits on the surface of the scales; but no spores or sporangia were found and the pits as shown in the published figures do not present the appearance of scars of sporangia.
The Rhaetic specimen originally named by Nathorst Androstrobus Scotti and afterwards transferred to the genus Lycostrobus was described in Volume ii.[1421]
Androstrobus Nathorsti Seward.
The type-specimens were obtained from the Wealden beds of Sussex: they were referred to the genus Androstrobus on evidence which cannot be regarded as decisive[1422]. A fairly stout axis, 6·5 cm. long, bearing spirally disposed sub-triangular scales hexagonal in section and attached to the axis by a broad base; the scales, or sporophylls, are 1–1·5 cm. long and gradually tapered towards a pointed or slightly rounded apex. Near the proximal end of some of the sporophylls there are regularly arranged polygonal depressions which may be impressions of microsporangia. The regular disposition of the depressions is a striking feature and in contrast to the less regular reticulum exposed after the removal of the sporangia from the microsporophyll of a recent Cycad. An examination of the cuticular membrane of the microsporophylls shows that the epidermal cells have thick and straight walls[1423], characters consistent with the supposed Cycadean affinity of the strobilus.