STUDIES IN THE FLORA OF INDIA­ 32. ON THE GENUS GANGAMOPTERIS McCOY

P. K. MAITHY Birbal Sahni Jnstitute of Palaeobotany, Luckoow

ABSTRACT 1902; WALKOM, 1922, 1938; TEICHERET, 1943), South Africa (SEWARD et al., 1908; The genus Crmgamopleris McCoy is an important constituent of the Glossopteris flora. Several views DU Ton, 1927, 1929; PLUMSTEAD, 1956, have been expressed in past for its specific de­ 1958), Belgian Congo (H4>EG & BosE, 1960), limitation but none of them have so far been proved Angola (KRISHNAN, 1960); Rhodesia & to be very satisfactory. In the present paper Nyassaland (LACEY, 1961); Brazil (WHITE, some suggestions are proposed for the specifIc delimitation of the genus on the basis of external 1908; CARRUTHERS, 1869; LUNDQUVIST, morphology of leaves. 1919; DOLJANITI, 1954a, b); Argentina (ARCHANGELSKY, 1957, 1958) and Antartica (PLUMSTEAD, INTRODU~TION 1962). Some species of Ganga­ rnopteris have been described from Angara ANGAMOPTERIS McCoy is an im­ flora (ZALESSKY, 1918). The assignment portant member of the Glossopterideae. of these leaves to Gamgamopteris is not free G It was first described by McCoy (1847) from doubts, because so far the relationships from Australia. Since then a large number between the two flora, i.e. Angara flora of leaves have been assigned to it from and Glossopteris flora is not well established. various Lower Gondwana formations of Gangamopteris is probably the oldest the Southern hemisphere. In recent years member of the Glossopteris flora and in Srivastava (1956), H4>eg & Bose (1960) every country is first to appear, sometimes and Maithy (1965) have described the epi­ alone or with Glossoptertis. In comparison dermal structure. Gangarnopteris fructifica­ to its wide geographical distribution the tions have been described by Plumstead vertical range is limited, therefore, the (1960, 1963) from South Africa, viz. Otto­ genus is of considerable stratigraphical haria buriadica, Ottokaria transvaalensis and importance. The genus is more common Vannus gondwanensis. Ottokaria tYFe of in the Lower and is rare or absent fructification are also known to be attached in the Upper Permian. In India Ganga­ to Glossopter·is indica. Plumstead (1958: mopter·is is dominant in Talchirs and 65) opined that Ottokaria may be the fructi­ Karharbaris, whereas in Damudas it is fication of both the genera, Gangamopteris represented by only one definite species. and Glossopteris. From Raniganj stage about six species of So far very little is known about the habit Gangamopteris are known but the identity and growth of Gangarnopteris. Some clusters of some seems doubtful. In Australia it of leaves belonging to G. obovata and G. has been recorded along with marine fossils indica were recorded from Wankie, South in the Lower Marine series about 2000 feet Rhodesia, by Plumstead (1958a) and on the above its base and it reaches to the maxi­ basis of these specimens, she concluded mum development in the Lower Series of that they were mainly deciduous, woody Coal Measures and gradually declines during of arborescent habit with leaves the Upper Coal Measures. In Africa it growing at short shoots, in clusters at fairly occurs both in the Dwyka and Ecca series wide i"ntervals from the woody stems. of the Karoo system and had been found by Leslie (1921) at Vereeninging below the DISTRIBUTION OF Dwyka Tillite. Above the Tillite' it is GANGAMOPTERIS is common in Middle Ecca, but not higher. It is found both in Brazil, Argentina and Gangamopteris is widely known from Antarctica from beds regarded as Lower India (FEISTMANTEL, 1879, 1881, 1882, Permian in age. 1886; SEWARD, 1907), Australia (FEIST­ Gangamopteris was first described by MANTEL, 1890a, b; McCoy, 1847; ARBER, McCoy (1847) from New South Wales as

46 MAITHY - STUDIES IN THE GLOSSOPTERIS FLORA OF INDIA - 32 47

Cyclopteris? angustifolia for a leaf showing doubtful whether the genus Gangamopteris netted venation as in Glossoptertis, but should not be merged in Glossopteris". This without a midrib. This specimen was referred has also been su pported by Wal kom (1922). to Cyclopten's with some hesitation by McCoy Surange & Srivastava (1956) favoured this but at the same time he thought that the view on the basis of the cuticular studies difference in the venation is of the generic and stated" it is thus evident that Glossop­ value. Later McCoy (1860) examined a teris, Gangamopteris and Paldeovittaria large number of specimens from the cannot be regarded as natural genera" Bacchus - Marsh Sandstone, Victoria and and supported further splitting of these came to the conclusion that the anastomo­ genera. However, the separate retention sing of viens and the absence of a midrib of Gangamopteris from Glossopteris seems are constant feature and hence, he proposed to be essential because in only few cases the generic name Gangamopteris. the specimens with a fructification or The original diagnosis given by McCoy cuticle are found. was later modified by Feistmantel (1879) In certain case the generic identificatIOn and Arber (1905)., In recent years the between Glossopteris and Gangamopteris epidermal structure has been described by becomes difficult. Several of the Glossop­ Srivastava (1956), Heg& Bose (1960). Neoggerathopsis has amply shown that the On the other hand leaves with different combination of the external morphological morphological features viz., Palaeovittaria features, i.e. Leaf shape, apex, base and kurzi and Glossoptfris intennittens have venations can more advantageously be used similar cuticles. Thus, these cuticular for specific delimitation. This has also been evidences leads us to the conclusion. that supported by the epidermal studies of these these homogenous looking leaves are hetero­ leaves. genous in nature and their number of species On the basis of the above evidences a is comparatively much more larger than critical morphological study of several originally thought to be on external morpho­ hundred Ganga~nopterisleaves from the logical character. This is also supported Talchir - Karharbari beds was undertaken by the recen t discoveries of fructifications to evaluate a system for specific delimita­ (Plumstead, 1956). The study of the tion. From an analysis of this study it morphology of dispersed spores from the seems that the combination of the following Lower Gandwans of India (Bharadwaj, characters can be applied with greater 1960) also supports this view. reliance for the specific circumscription. Thus, these evidences raises the problem for specific iden tification of those similar 1. Shape: looking leaves, one with a cuticle and the a. Sy11'l.metry: Leaves either bilaterally other without a cuticle;> The most symmetrical (G. major, G. cyclopteroides) or suitable course for the present seems to asymmetrical (G. angustifolia, G. buriadica, describe the leaves with a cuticlE and var. acrodeltoides). wi thou t cuticle under two different b. Gull'ine of leaf: Various types of out­ specific names. In the latter the circum- lines are known among Gangamopteris scription of species will be mainy based upon leaves. They may be linear, lanceolate, the external morphological characters, i.e. elliptical, spathulate or obovate. impression species whereas in the former the cu ticular structure will form the main 2. Apex: basis for specific identifications, i.e., cuti­ The apex seems to be an important cular species. Although, this method of feature and great reliance on this character approach might result into a nomenclatural can be stressed for specific delimitation. duplication, but it ,,,,ill nevertheless resolve The apex may be acute, acuminate, obtuse, much confusion between the cuticular and broadly rounded and mucronate. non-cuticular forms. The occurrences of Gangamopteris leaves 3. Base: in the form of impres~ions are in such a large number that one cannot neglect their The base of the leaves may be petiolate or contracted. This can also be used in study for s~ratigraphical purpose. Several combinations with other characters. views have been expressed in past for specific delimitation, but till now none seems 4. Venation: to be very satisfactory. McCoy (1874) and Feistmantei (1879, 1881, 1890) insti­ a. !VIedian velns tuted number of species from Australia and (i) Median region has a prominent India on the basis of the leaf shape and groove (G. stephansoni Plumstead). venation.. However, Arber (1905) adopted (ii) Median region occupied by sub­ a broad defination of species and regarded parallel prominent veins from base many of the species described by McCoy and to apex forming elongate rectan­ Feistmantel irrelevant and merged them gular meshes. (G. kashmirensis together under one species. This broad­ Seward) based concept of specific delimitation was (iii) Median region occupied by sub­ later followed by Seward (1910) and sup- parallel veins, prominent at the MAITHY - STUDIES IN THE GLOSSOPTERIS FLORA OF (NDIA - 32 49

base and gradually becomes teris buriadiea Feistmantel (1879) has evanescent at the apex (G. truncate apex. Feistmantel (1879) describ­ eyclopteroides F eistm.). ed under Gangamopteris major two types (iv) Median region occupied by of leaves. One rhomboidal in shape with obscure or diffused veins (G. ± acute apex (PL. 14, FIG. 3) and the other major Feistm.). spathulate in shape with obtuse apex (PL. (v) Median region occupied by 26, FIG. 2). On the basis of reent morpho­ polygonal or hexagonal meshes logical evidences the latter type of specimens from base to apex (G. obliqua needs a separation from G. major under a McCoy). distinct specific name. Several views have been expressed in b. Secondary veins: past and in recent years to consider Ganga­ (i) Course of veins: The courses of mopteris eyeloptel'oides Feistman tel (1879) veins depend upon the angle of as synonymous to G. obovata (CarL) White emergence. The veins are erect­ (1908) and the latter name has also been straight (G. lJ'u,riadiea), erect-ob­ used by several workers in view of priority. Jique (.G, angustifolia) or arched The recent morphological studies show (G. eyclopterol:des). Secondary veins that the two species should be kept separate. may be straight or flexuous. G. obovata (Carr.) White has elongate ob­ (ii) Meshes: The forms of meshes are ovate shape and ± broadly rounded apex trapezoid, rectangular, hexagonal whereas G. eyelopteroides has lanceolate or polygonal. The size of the shape and obtuse apex. In the former the meshes may be more or less meclian veins are ± diffused at the base uniform, longer and broad near whereas in the latter it is prominent at the the median region and narrow base and evanescent at the apex. and short near the margins or The survey of past literatures on Ganga­ the formations of meshes are mopteris shows that new species have been rare. The enclosed mesh area established, even though the leaves are are more or less smooth or may incomplete. As a result of which in some have fibers like structures. In cases the apical and the basal portion of the addition to this, statistical datas same leaf have been designated under two can be also taken in to consi­ distinct specific names. Feistmantel des­ deration, viz, density of veins, cribed two species of Gangamopteris from angle of emergence of secon­ the Permian beds of Tasmania, viz. G. dary veins and the maximum eonspieua and G. mersyensis. The former wid th region of the leaf from species is based on the apical part whereas apex. the later on the basal part. These two Taking into consideration the above species which are based on two different morphological characters, the Gangamop­ portions of the leaves appears to be synony­ teris leaves published by early workers mous in view of the close similarity in their needs redefination. A number of species venation. Thus, in view of this fact for appears to be synonymous while several further morphological establishment of new others appear to be morphologicaly distinct. species one should take only complete Feistmantel (1879,1886) instituted a number specimens under consideration and due care of varieties of G. eycloperoides from the should be taken for incomplete leaves. Lower Gondwana formations of India. A So far about twenty species of Ganga1110p­ careful examination shows that most of teris are known from the Lower Gondwana them are superfluous (viz. G. e)'elote1'oides of Southem hemisphere. Recent cuticular var. subaurieulata, G. eyelopteroides var. studies and records of fructification have aerolata) except one viz. G. eyelopteroides pointed that these number of genera var. aeuminata. which should be considered amongst these homogenous forms are far as a distinct species due to the acute apex greater than what it was originally thought and ± erect veins. Gangamopteris buria­ to be. In the present study an attempt has diea var. aerodeltoides Dolianiti (1954) should been made whether it is possible to seggreate also be separated under a new species, The further the leaves of Gangamopteris in species is characterizecl by asymmetrical groups on the basis of morphology. A shape and deltoid apex whereas Gangamop- critical analysis of the various characters of so THE PALAEOBOTANIST

Gangamopteris leaves present that it could meshes broad and elon­ be further spJitted into two main groups gate near median region. and several sub-groups. A scheme for the classification and synopsis for identification 8. G. cyclopteroides var. acuminata Feistm. is presented here. This scheme is tentative Secondary veins froming and can be modified when more details are polygonal meshes of more available. or less uniform size. Group I: Median region occupied by subparallel veins forming elongate-rectan­ 9. G. conspicua Feistm. gular meshes. Leaves linear, lanceolate, (Syn. G. mersyensis Feistm.) elliptical or spathulate in shape. b. Spathulate shape Secondary veins arched A. Leaf Asymmetrical: forming elongate rectan­ Linear shape, acute apex. gular meshes. 1. G. angustifolia McCoy 10. G. spathulata McCoy Lanceolate - spathulate shape, apical portion deltoid, apex acuminate. Secondary veins erect, forming elongate rectan­ 2. G. buriadica var. acrodeltoides Dolianiti gular meshes. B. Leaf Symmetrical: (i) Leaf has a distinct median groove 11. G. maJor Feistmantel rounded-oval shape, apex obtuse. (iii) Apex obtuse a. Lanceolate shape 3. G. stephensom' Plumstead (ii) Median region occupied by sub- 12. G. cyclopteroides Feistmantel parallel veins. b. Elongate obovate shape Median veins prominen t from base to apex. Lanceolate shape, 13. G. obovata (Carr.) White acute apex. (iv) Apex broadly rounded 4. G. kashmirensis Seward a. spathulate shape Median veins prominent at the base and gradually gets diffused. 14. G. ? maJor (Feistm.) Maithy a. Fibres present in between b. Obovate shape the meshes. Lanceolate shape, obtuse apex, secondary 15. G. clar/~eanaFeistmantel veins ftexuosus. (v) Apex truncated 5. G. fibrosa Maithy a. LanceoJat,e shape b. Fibres absent in between the meshes. 16. G. buriadica Feistm. (i) Apex pointed mucronate Group II. Median region is occupied by a. Elleptical shape, veins veins more or Jess hexagonal in shape. course oblique form­ Leaves mostly obovate in shape. ing elongate rectangular (i) Apex broadly rounded meshes. a. oblong shape 6. G. mucronata Maithy 17. G. castellanosi Archangelsky b. Lanceolate shape, veins erect oblique forming b. obovate shape rectangular meshes. 18. G. intermedia Maithy 7. G. mosesi Dolianiti (ii) Apex acute (ii) Apex acuminate a. Obovate shape a. Lanceolate shape. Secondary veins forming 19. G. obliqua McCoy MAITRY - STUDIES IN THE GLOSSOPTERIS FLORA OF INDIA - 32 51 REFERENCES

ARBER, E. A. N. (1902). The clarke collection McCoy, F. (1847). Op the fossil botany and Zoo­ of fossil plants from New South '>-'ales. Quart. logy of the rocks associated with the coal of I geol. Soc. s. AF 58' 1-26. Australia. Ann. Mag. nat. Hist. 20: 145, 226, Idem (1905). The Glossopteris Flora. I.ondon. 298 ARCHANGELSKY, S. (1957). Las Glossopterideas Idem (1860). A commentary on "A communi­ del Bajo de la Leona. Rev. Assoc. Genl. A "gen­ cation made by the Rev. W. B. Clarke" & C. tina 12(3). 135-164. Trans. ,-oy. Soc. Vict01'ia 5. 98. ARCHANGELSKY, S. (1958). Estudio Geologicov Idem (1874). Podromas of the Palaeontology of Palaeontologico del Bajo de la Leona. A eta. Victoria Sec. II,' 11-13. Geol. Lillona.. 2: 5-153. PLlJMSTEAD, E. P. (1956). On Ottokaria, the fructi­ CARRUTHERS, W. (1869). On the remains fication of GanganlOpte,-is. T,'ans. geol. Soc. S. from the Brazilian Coal beds with remarks on A/I'. 59: 211-236. the genus Fle11lingitf.S. Geol. Mag. 6 151-156. Idem (1958). Further fructification of the Glos­ DOLJANITI, E. (l954a). Gangamopteris angusti/oliae sopteridae and a provisional classification based G. buriadica. Div. de. geol. Min. 87: 1-6. on them. Ibid. 61: 52-76. Idem (1954b). A flora do Gondwana inferior em Idem (1958a). The habit of growth of Santa Catarina, V. 0 genero Gangamopteris. Glossopterideae. Ibid. 61: 81-94. Ibid. 89 L: 1-12. Idem (1962). Fossil floras of Antartica. Trans. Du TOIT, A. L. (1927). Some fossil plants from the Antantic Expedition 1955-58, Scientific Reports Karroo system of South Africa. Ann. S. A/,-. No.9: 1-154. Lcndon. Mus. 28(4). 370-393. Idem (1963). Vannus gondwanensis, A new Idem (1929). A short review of the Karroo fossil Gangamopte,-is fructification from the Trans­ flora. C. R. II. XV into Geol. C;o"g'-.. 239-251. vaal, South Africa. Palaeobotanist 11: 106­ FEISTMANTEL, O. (1879). Fossil flora of Gondwana 114. System. The flora of the Talchir-Karharbari SAHNI, B. (1923). On the structure of cuticle in beds and supplement. Palaeont.indica. Ser. 12. Glossopte,'is angusti/olia Brongn. Rec. geol. 3(1): 1-64. SUl'v. India 54(3): 277·280. Idem (1881). Fossil Flora of Gondwana System. SEWARD, A. C. (1907). Permo- The flora of the Damuda-Panchet division. plants from Kashmir. Ibid. Ibid 3(2,3). 1-149.' Idem (1910). Fossil Plants. 3: Cambridge. Idem (1882). Fossil flora of Gondwana System. SEWARD, A. C. & LESLIE, 1'. N. (1908). Permo­ [-'ossil flora of the South Rewa Gondwana Carboniferous plants from Vereeninging. Quart. basin. Palaeont. indica Ser. 4(1) 1-52. J. geol. Soc. Land. 64: 109-125. Idem (1886). Fossil flora o[ Gondwana Svstem. SEWARD, A. C. & \OVOODWARD,A. S. (1905). Permo­ Fossil flora of some of the Coalfields in Western Carboniferous plants and Vertebrates from Bengal. Ibid. 4(2). 1-66. Kashmir. Palaeont. indica. N .S. Mem. 2: Idem (l890a). Geological and Palaeontological 1-13 . relation of the coal and plant bearing beds of SRIVASTAVA, P. N. (1956). Studies in the Glos­ Palaeozoic and Mesozoic age in Eastern sopteris flora of India-4. Glossopteris, Ganga­ Australia and Tasmania with snecial reference Inopte,.,:s and PataeoviUa,'ia, Palaeobotanist to fossil flora. Mem. geol. -Surv. N.S.W. 5(1): 1-45. (Palaeont.) 3 1-183. SURANGE, K. R. & SRIVASTAVA, P. N. (1956). Idem (IR90b). Uhlonosne UtvaryVTasmanii. Pmze. Studies in the Glossopteris flora of India-5. H.pEG, O. A. & BOSE, M. N. (1960). The Glossop­ Generic status of Glossopteris, Gangamopteris teris flora of the Belgian Congo with a note on and Palaeovitlaria. Ibid. 5(1): 46-49. some fossil plants from the Zambesi Basin TEICHERT, G. (1943). The distribution of Ganga­ (Mozambique). Al'I1L Mus. Royal Congo Beige. mopteris in the Permian of 'Western Australia. Tervuren (Belgique) Ser. ROSciences geologiques Aust. J. Sci. 6(3): 79-80. 32' 1-99. W ALKOM, A. B. (1922). Palaeozoic floras of Queens­ LACEY, W. S. (1961). Studies in the Karmo Floras land Pt. 1. The flora of the Lower and upper of Rhodesia and Nyssaland. Pt. 1. Geological Bowen series. Qd geol. Surv. Publ. No. 270: