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Further Observations on Indian Lower Gondwana Sphenophyllales

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Further Observations on Indian Lower Gondwana Sphenophyllales FURTHER OBSERVATIONS ON INDIAN LOWER GONDWANA SPHENOPHYLLALES P. Ie MAITHY Birbal Salmi Institute of Palaeobotany, Lucknow-226007, India ABSTRACT New morphological details and the possible habit of Trizygia speciosa Royle are described alongwith two new forms of Sphenophyllales, Paratrizygia rhodesii (Rigby) n. comb. and Parasphenophyllum crenulatum sp. novo from the Damuda Series of India. INTRODUCTION has two distinct ridges, which do not alternate from one internode to the next, but are co'ntinuous. The internodal length T'RIZYGIAthe only SphenophyllalesSPECIOSA Royleknown(1839)fromis of the stem varies from 0·4-2·2 cm and the the Indian Lower Gondwana succes- width from 0·1-0·2 cm. The distance in sion. Recently, several specimens of Trizygia between two nodes show progressive increase speciosa have been collected from the Rani• in length from apical to basal end. In ganj Formation of Raniganj Coalfield. The cellulose pull of the stem, its substance study gives new information o'n the morpho• generally appears to be black or dark logy and the possible habit of plants. brown, but at some places it is light brown The same is detailed here along with the and translucent. At such points the stem record of two new forms of Sphenophyllales substance shows xylem elements with scalari• from the Lower Gondwana of India. form thickenings (Text-fig. 2A) or bordered The specimens are preserved in the form pits (Text-fig. 2B). Bordered pits are in of impressions or compressions. Observa• one row, occasionally in two rows, circular• tions. on epidermal structures and other ana• oval in shape with circular pore. They are tomical structures were possible by means of either contiguous or arranged separately. cellular pulls from compressions. For the Bordered pits have also been reported identification of Sphenophyllales the nomen• earlier by Pant 2nd Mehra, (1963), but it clature proposed by Asama (1970) has been is not definite if this is of secondary wood. followed. These elements are flanked on either side All the figured specimens in this paper by surrounding fibres. The stem surface are preserved at the Museum of Birbal shows elongate-rectangular epidermal cells, Sahni Institute of Pdaeobotany, Lucknow. which are placed end to end by their end walls. DESCRIPTION Leaves are arranged in whorls on nodes (PI. 1, fig. 1). Each whorl comprises Trizygia Royle, 1839 six leaves. The six leaves are arranged in three distinct pairs (Text-fig. 1A), i.e. Trizygia speciosa Royle, 1839 two bigger pairs and one small pair. Leaves PIs. 1, 2, figs. 1-9; Text-figs. 1-6 are attached ± at right angles to the axis by their cuneate base. Two bigger Synonymy- See Maheshwari, 1968, p. 283. pairs of leaves occupy the lateral position while the third smaller pair occupies the Two hundred speCImens of Trizygia central position in preserved condition. speciosa have been examined. All of them A leaf whorl encircles completely round are either incomplete at the apical or basal the node (Text-fig. 1B) and not one side ends, or both the ends. of the node as Feistmantel (1879, p. 166) The stems bearing the leaves are slender, believed them to be. The whorls are sprea• unbranched, articulated with slightly swollen ding horizontally. During fossilization the nodes (PI. 1, fig. 1). The internodal region lamina and the a,xis aYe so preserved tha.t ~66 MAITHY - OBSERVATiONS ON INDIAN LOWER GONDWANA SPHENOPHYLLALES 267 A o c TEXT-FIG. 1. - A, leaf whorl laterally preserved X l·S. B, leaf whorl dorsi-ventrally preserved X l·S. e, venation in the lateral leaf X 3. D, venation in the central small leaf X 3. the two bigger pairs of leaves are arranged run ± straight. The angle of divergence in on the lateral sides and the smaller pair between two veins is 5°. Interconnection in the centre. The lateral pairs of leaves in between the veins are absent and the are ± double in size than the central pair. interstitial fibres too. Lateral leaves are ± asymmetrical in Epidermal structure of leaves have earlier outline, whereas the central leaves are been reported by Pant and Mehra (1963) symmetrical. Leaves of the lateral pairs and Maheshwari (see Surange, 1964). Epi• are elongate - ovate, apex obtuse, base dermal pulls of the leaves show sinuous cuneate and entire margin. The leaves of outlines in which some walls appear faint, central pair are ovate, apex obtuse, base while others are darker. In fact, the cells cuneate and entire margin. In all the arrangement as a whole indicates that leaves the inner margin are ± straight, in these pulls, the presence of two trans• while the outer margin has a strong cur• lucent layers of epidermis overlapping each vature. A progressive increase in the size other and both of them have sinuous• of leaves is well marked, in each successive walled cells, alongwith the straight-walled whorls from apical to basal end. Lateral rectangular cells of vein area. Epidermal leaves measure 0·5-2·6 cm in length while cells are 70-14-0 [J. in length and 15-40 [J. the central leaves measure 0·25-1·5 cm in in breadth. The cells of non-stomatiferous length (see Table 1). epidermis are longitudinally oriented and A single vein enters at the base of leaf tend to be in series parallel to the veins (Text-fig. Ie, D), which dichotomises into (Text-fig. 2D). The walls are seemingly less two and then into four veins. The outer sinuous. The cells of the other overlapping pair of veins divides only once before layer are irregularly ananged and their reaching to the margin. The inner pair walls are deeply sinuous (PI. 2, fig. 8; subsequently dichotomises 1, 2 or 3 times. Text-fig. 2E). The cells measure 60-80 [J. As a result of which 10-18 veinlets are at in size. The stoma.ta are haplocheilic having the apical margin of the lateral leaves and thickened lateral lamellae, measuring 18-20 [1. 10-12 veinlets in the central leaves. Veins in len~th. The sl.lbsidiary cens are like ~68 THE PALAEOBOTANIST TEXT-FIG. 2. - A, tracheids of foliage shoot showing spiral thickenings X 500. B, tracheids of foliage shoot showing single row of bordered pits X 500. C, celts over the vein region near the basal portion of leaf X 400. D, celts of the vein cells and the non-stomatiferous surface of leaf X 400. E, celts of the stomatiferous surface X 400. ordinary epidermal cells and the polar and ridges are continuous (PI. 1, fig. 3). subsidiary cells are not different from lateral Occasionally, the axes are branched. The ones. The basal most region of the leaf, width of the axes vary from 2-4 em. i.e. ± 2 mm from point of attachment with In some cases a distinct groove 1·5 to stem show distinct cellular structure from 2 mm broad is present in the middle (PI. 1, the laminar portion of leaf. Cells in this fig. 4). The internodal length varies from portion (PI. 2, fig. 7; Text-fig. 2C) on both 0·6 to 1·6 mm long. The nodal region of the surfaces are thick-walled, rectangular, both the halves may either fall in one level trapezoid, hexagonal in outline, margin or may be arranged at different levels (PI. 1, straight and arranged end to end. Cells are figs. 2, 6). Branch scars are preserved on 100-120 fl. long and 15-20 fL broad. Cell nodes. Branch scar is a rounded (PI. 1, wall ± 3 fl. thick. fig. 5; Text-fig. 3B) depression, measuring A large number of leafless articulated axes 1·5-2 mm in dimension. Occasionally, a are found alongwith these foliage shoots carboni sed crust of ± 4-5 mm broad, is pre• (PI. 1, figs. 2, 4; Text-fig. 3A, B). The served on both the marginal side of stem. axes are preserved in form of impressions, This carbonised crust, probably represents compressions or casts. The axes are arti• the cortical part of the axes. Usually the culated and of varying length. The grooves leafless articulated axes are found lying Pages 269-270 TABLE 1- SHOWING THE VARIATIONS IN THE SIZE OF LEAVES AND THE DISTANCE IN BETWEEN TWO INTERNODES IN DIFFERENT SPECIMENS OF TRIZYGIA SPECIOSA. (ALL MEASUREMENTS ARE IN mm UNLESS MENTIONED) L = Lateral pair of leaves, C = Central pair of leaves SPECIMEN SIZE OF KUMBER NUMBER PLANT OF WHORLS 5'5 em 9 whorls Size of leaves in sueees- I 2 3 4 5 6 7 8 9 sive whorls L=2 L=4 L=5 L=7 L=8 L=8 L=9 L=12 L=12 C=? C=2 C=2 C=2 C=2·5 C=2'5 C=4·3 C=4 C=4 Length of internodes in 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 between two nodes 3 5 5 6 6 7 7'5 7 2 13 em 13 whorls Size of leaves in sueees- I 2 3 4 5 6 7 8 9 10 II 12 13 sive whorls ? L=9 L=IO L=II L=13 L=16 L=17 L=20 L=21 L=22 L=? L=24 ? Length of internodes in 1-2 2-3 3-4 4-5 5·6 6·7 7-8 8-9 9-10 10-11 11-12 between two nodes ? 7 8 9 10 II 12 13 14 IS IS 3 12 em 15 whorls Size of leaves in sueees- I 2 3 4 5 6 7 8 9 10 II 12 13 14 IS sive whorls L=5 L=6 L=8 L=10 L=12 L=13 L=14 L=? L=15 L=16 L=17 L=18 L=19 L=20 L=19 ~ C=2·5 C=3'5 C=4 C=5 C=5'5 C=' C=? C=? C=7 C=7 C=7·5 C=8 C=9 L=10 C=11 Length of internodes in 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8·9 9-10 10-11 11-12 12-13 13-14 14-15 between two nodes 5 6 7 8 8'5 9 9 9 10 10 II 12 13 14 4 15 em II whorls Size of leaves in sueees- I 2 3 4 5 6 7 8 9 10 II sive whorls ? ? L=15 ? ? L=? L=23 L=' 24 L=' L=26 L=' Length of internodes in C=9 C=11 C=12 C=13 C=14 C=15 C=? between two nodes 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 10-11 7 7 10 11 12 14 16 18 19 ? 5 6 em 9 whorls Size of leaves in sueees- I 2 3 4 5 6 7 8 9 sive whorls ? L=7'5 L=7·5 L=IO L=12 L=I1-5 L=12 L=13 L=13 C=2 C=2 C=3 C=4'5 C=4'5 C=5'5 C=5·5 C=5·5 Length of internodes In 1·2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 between two nodes 6 6 7 7 7 8 9 9 6 7'5 em 12 whorls Size of leaves in sueees- 1 2 3 4 5 6 7 8 9 10 II sive whorls L=6 L=6 L=10 L=12 L=12 L=14 L=14 L=14 L=15 L=16·5 L=18 C=2 C=2·5 C=4 C=4·5 C=4'5 C=5 C=5 C=5 C=6 C=6·5 C=7 Length of internodes in 1-2 2-3 3-4 4-5 5-6 6·7 7-8 8-9 9-10 10-11 between two nodes 5 6 7 7 8 8 7·5 8'5 9 10 7 8 em 6 whorls Size of leaves in sueees- I 2 3 4 5 sive whorls L=16 L=17·5 .L=20 L=20 L=21 Length of internodes in be- C=7 C=7'5 C=10 C=IO C=II tween two nodes 1-2 2-3 3·4 4-5 5-6 12 13 IS 16 20 .-\11 attempt has been made to place the specimens in a order to mark the parellelism in sIze of dIfferent specimens and to demonstrate the region, to which position of plant it belongs.
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