Fossil Woods of Leguminosae and Anacardiaceae from the Tertiary of Assam

FOSSIL WOODS OF LEGUMINOSAE AND ANACARDIACEAE FROM THE TERTIARY OF ASSAM

U. PRAKASH & P. P. TRIPATHI Birbal Sahni Institute of Palaeobotany, Lucknow

ABSTRACT were prepared from different parts of the Three fossil woods from the Tertiary of Assam petrified woods. This helped us to find are described here. One, resembling the modern out the range of variation. wood of Lannea, is from a road cutting at mile-stone 9 on Dimapur-Diphu road in Mikir Hills, and the others comparable with Adenanthera and Swin!onia SYSTEMATIC DESCRIPTION are from near the town of Hailakandi (24°26'N; 92°32'£) in district Cachar. Recently, these have Family - LEGUMINOSAE been briefly described by us (Prakash & Tripathi, 1967, 1968). Adenantheroxylon Prakash & Tripathi, 1968 INTRODUCTION Adenantheroxylon pavoninium Prakash & Tripathi, 1968

CONSIDERof TertiaryI JGdepositsthe extentin Assam,and Sizenot The fossil described here is a piece of many plant fossils are known so far. petrified secondary 'Noad measuring about It is because the area is much disturbed 5·6 cm. in length and 2 cm. in diameter. geologically and covered with thick forests The preservation of the fossil is not very which make it difficult to collect the plant satisfactory, due to which the structures fossils. Whatever little is recorded is by are not very clearly visible even under the Chowdhury, Prakash and their associates high power of a microscope. on fossil woods (CHOWDHURY,1936, 1938; Topography - Wood diffuse-porous (PL. CHOWDHURY& GHOSH,1946; CHOWDHURY 1, FIG. 1). Growth rings indistinct, appear• & TANDAN, 1949; GHOSH, 1956; EYDE, ing to be delimited by smaller vessels. 1963 ; PRAKASH,1966; PRAKASH& NAVALE, Vessels visible with the naked eye as pin• 1963) and Lakhanpal (1952, 1955a, 1955b) pricks on the cross surface, medium to large on leaf-impressions and fruits. in size, usually solitary, sometimes in short The present study is concerned with radial rows of 2, rarely 3-4 (PL. 1, FIG. description and interpretation of fossil woods 1; PL. 1, FIG. 5), somewhat graded, being of Adenanthera, Swintonia and Lannea be• large in the early wood, 3-7 per sq. mm.; longing to the families Leguminosae and tyloses absent but black gummy deposits Anacardiaceae. \Vood of Lannea was col• seen in some vessels. Parenchyma para• lected by the senior author in 1963 from tracheal and apotracheal; paratracheal a road cutting at mile-stone 9 on the Dima• parenchyma vasicentric, rarely aliform and pur-Diphu road in Mikir Hills, while those aliform-confluent joining two adjacent ves• of Adenanthera and Swintonia were· sent sels (PL. 1, FIG. 1; TEXT-FIG. 1); paren• to us in June 1964 by Mr. A. N. Datta, chyma sheath 2-6 cells thick around the Vijnan Mandir Officer, Hailakandi, district vessels; apotracheal parenchyma appears Cachar, Assam. These were collected from to be diffuse with crystals. Xylem rays near the town of Hailakandi (24°26'N; not visible to the naked eye, distinct only 92°32'E). under the microscope, 1-3 seriate, mostly The age of the fossil woods is Tertiary, biseriate, rarely uniseriate and triseriate (PL. probably Middle Miocene, possibly being 1, FIG. 3; TEXT-FIG.2a, b, c), 20-60 fl. broad derived from the Tipam sandstones exposed and 2-30 cells or 40-300 fl. high, 14-22 per in the vicinity of the fossil occurrence mm.; ray tissue homogeneous, rays homo• (EVANS,1932; DAS GUPTA,EVANS,METRE cellular consisting only of procumbent cells & VISVANATH,1964). (PL. 1, FIG. 3; PL. 1, FIG. 7). Fibres not The preservation of the structural details very clearly visible due to bad preservation of the fossil woods is fairly good. In order of the tissues, arranged more or less in radial to make a detailed study, many sections rows. 22 PRAKASH & TRIPATHI - FOSSIL WOODS OF LEGUMINOSAE AND ANACARDIACEAE 23

TEXT-FIGS. 1-3 - Adenantheroxylon pavoninium Prakash & Tripathi (Semi-diagrammatic camera luciCla drawings). 1 - Cross-section showing the distribution of parenchyma (p). x 33. (Slide No. 3262). 2. a - Uniseriate xylem ray with procumbent cells. X 300. (Slide No. 3263). b - Biseriate xylem ray with procumbent cells .. X 300 (Slide No. 3263). c - Triseriate xylem ray with procumbent cells. X 300. (Slide No. 3263). 3 - Magnified vestured intervessel pits. X 766. (Slide No. 3264). 24 TIlE PALAEOBOTANlST

Elements - Vessels thin walled, walls In both the fossil wood and the modern about 4-8 fl. thick, tangential dialTieter wood of A. pavonina, Linn. (F.R.I. slide 144-204 fl., radial diameter 142-260 fl., oval no. A 3657(B 5659) the vessels are large to round in shape when solitary arid well to medium-sized, the intervessel pit-pairs preserved, most of the vessels irregular in are alternate, bordered, the parenchyma shape probably due to pressure during is para tracheal and apotracheal; paratra• fossiliza tion (PL. 1, FIG. 1), those in radial cheal parenchyma vasicentric, rarely aliform groups flattened at the places of contact and aliform-confluent; apotracheal paren• (PL. 1, FIG. 5); vessel-members with trun• chyma diffuse; the rays are 1-3 (mostly cate ends; perforations could not be as• biseriate) seriate and homogeneous, and certained; intervessel pit-pairs not very the fibres are non-libriform and non-septate. distinct, appear bordered and vestured (PL. However, the chambered parenchyma has 1, FIG. 6; TEXT-FIG. 3); vessel-ray and not been clearly seen in the fossil wood like vessel-parenchyma pits not observed. that of the modern wood of A. pavonina. Parenchyma cells thin-walled, about 64-240 Because of the close resemblance of the fl. in length and 8-28 fl. in diameter; cham• fossil wood with the wood structure of the bered parenchyma appears to be present. modern genus Adenanthera Linn., it has Ray-cells thin-vvalled, round to oval in shape been assigned to a new genus Adenantheroxy• in tangential section; tangential diameter lon Prakash & Tripathi. It is specifically 16-24 fl., radial diameter 20-80 fl.. Fibres named as Adenantheroxrylon pavoninium in thin-walled with big lumina, walls 4 [J. thick, view of its near resemblance with the wood somewhat irregular in shape due to pressure of the modern species Adenanthera pavonina during fossilization, non-septate, 400-1240 Linn. [J. in length, 16-20 [J. in diameter; interfibre The genus Adenanthera Linn. consists pits not preserved. of 5 species distributed through tropics of Affinities - There is a close agreement the Old World (Willis, 1957). The species in almost all the structural details of the A. pavonina Linn., with which the fossil present fossil wood with the wood struc• wood shows nearest resemblance, has a ture of the modern genus AdenantheraLinn. wide distribution, growing in east Hima• of the family Leguminosae (METCALFE& layas (ascending to 1233 meters in Sikkim), CHALK,1950; DESCH, 1957; MOLL& J ANS• Western Peninsula, Ceylon, Malaya Isles, SONIUS, 1914, FIG. 166; KANEHIRA,1924). Timor, China and Philippines (HOOKER, An examination of the thin sections, pub• 1879, p. 287; GAMBLE,1902, p. 287; TROUP, lished descriptions and photographs of the 1921, p. 485). species of Adenanthera reveals that the A large number of fossil woods of the present fossil wood shows nearest resem• family Leguminosae are known from India blance with the wood structure of A. pavo• and abroad but the present discovery forms nina, Linn. Our study included the exami• the first fossil record of Adenanthera. Its nation of thin sections of A. bholor Moon wood structure differs quite markedly from and A. pavonina Linn. and published des• all the known fossil woods of the Legumi• criptions and photographs of A .microsperma nosae. Teysm. et Binn., A. pavonina Linn. (MOLL & JANSSONIUS, 1914), A. bicolor Moon DIAGNOSES (DESCH, 1957) and A. intermedia Merrill (KANEHIRA,1924). Adenantlteroxylon Prakash & Tripathi The modern wood of A denanthera pavonina Linn. has been studied from a large number Wood diffuse-porous. Growth rings indis• of thin sections belonging to different speci• tinct. Vessels large to medium-sized, mens, and the variations seen are as follows. usually solitary sometimes in short radial The vessels are mostly solitary in some rows of 2 (rarely 3-4), round to oval in cross specimens, while they are in radial chains section; perforations simple; intervessel pit• in others; the parenchyma is diffuse, vasi• pairs vestured and alternate. Parenchyma centric to aliform, rarely confluent to usually paratracheal and apotracheal; paratracheal confluent with thicker sheaths around the parenchyma vasicentric, aliform and con• pores; the xylem rays are 1-3 seriate, mostly fluent; apotracheal parenchyma diffuse; " biseriate in some, while both uni- and biser• chambered parenchyma present. Xylem iates aremoreorless equal in other specimens. rays fine to very fine and short, 1-3 seriate; PRAI(ASH & TRIPATHI-FOSSIL WOODS OF LEGUMINOSAE AXD A 'ACARDIACEAE 25

ray tissue homogeneous; rays homocellular paratracheal and apotracheal; para tracheal composed of procumbent cells. Fibres non• parenchyma vasicentric, aliform and aliform• septate, semi-libriform with big lumina. confluent, forming 2-4 cells thick sheath around the vessels (PL. 2, FIG. 8; PL. 3, Adenantheroxylon pavoninium Prakash & FIG. 15; TEXT-FIG. 4); aliform-confluent Tripathi parenchyma occuring as short bands joining 2-3 vessels; apotracheal parenchyma in Wood diffuse-porous. Growth rings indis• long and short bands distributed irregularly tinct. Vessels large to medium-sized, round (PL. 2, FIG. 8; PL. 3, FIG. 15); parenchyma to oval in cross section, t.d. 144-204 [1., r.d. bands 3-6 cells thick. Xylem rays distinct 142-260 [1., mostly solitary, sometimes in with a hand lens on the cross-section of the short radial rows of 2 (rarely 3-4); 3-7 per wood, normally 1-3 (mostly 2) seriate (PL. sq. mm.; tyloses absent, black gummy 2, FIG. 10) and 15-90 !J. broad; fusiform deposits seen in some vessels; vessel-members rays with normal (PL. 2, FIG. 13)and trauma• with truncate ends; intervessel pit-pairs tic gum-canals also present (PL. 2, FIG. 12); vestured; perforations could not be seen. fusiform rays with normal gum-canals occa• Parenchyma paratracheal and apotracheal; sional, 6-12 seriate, but those with trau• para tracheal parenchyma vasicentric, rarely matic gum-canals frequent, 15-32 seriate; aliform and aliform-confluent joining two rays 14-18 per mm.; ray tissue heterogene• adjacent vessels; apotracheal parenchyma ous (PL. 2, FIG. 11; PL. 3, FIG. 16); rays diffuse; chambered parenchyma present. heterocellular, consisting of procumbent Xylem rays 1-3 (mostly 2) cells and 20-60 cells in the middle portion and upright [1. broad, 2-30 cells and 48-300 [1. high, cells at one or both the ends (PL. 2, FIG. 11; 14-22 per mm.; ray tissue homogeneous; PL. 3, FIG. 16); reddish-brown probably rays homo-cellular composed of procumbent gummy infiltration abundant in ray cells; cells. Fibres thinwalled, with big lumina, crystals present in ray cells. Fibres aligned non-septate, somewhat irregular in shape in radial rows in cross-section, interrupted due to pressure during fossilization, 400• by parenchyma bands. Intercellular canals 1240 [1. in length, 16-20 [1. in diameter. horizontal, both normal and traumatic, Holotype - B.S.I.P. Museum No. 3374~. confined to the xylem rays, 45-255 [1. in Locality - Hailakandi, district Cachar, diameter. Assam. Elements -- Vessels thin-walled, 4-6 [1. Horizon - Probably Tipam series. thick, t.d. 100-288 [1., r.d. 110-320 [1., round Age - Tertiary (Middle Miocene). to oval in cross-section, those in groups flattened at the places of contact; vessel• Family - ANACARDIACEAE members 220-700 fl. long, truncate or with tailed ends; perforations simple; intervas• Swintonioxylon Prakash & Tripathi, 1968 cular pit-pairs large, 8-12 [1., bordered, oval Swintonioxylon hailakandiense Prakash & to angular through crowding, with lenti• Tripathi, 1968 cular orifices (PI.. 2, FIG. 14); vessel-paren• chyma and vessel-ray pits not observed. The fossil described here is a piece. of Parenchyma cells thin-walled, round to oval de'cortica ted secondary wood measunng in" cross section, 75-225 [1. in length and about 8·0 em. in length and 3·0 em. in dia• 6-20 fJ. in diameter. Ray cells thick walled; meter. It is brown in colour showing satis- tangential length of procumbent cells 12-28 factory preservation. ,- [1., radiallength 68-124 [1.; upright cells 32-64 Topography - Wood diffuse-porous (PL. [1. in tangential and 20-56 [1. in radial length. 2, FIG. 8). Growth rings indistinct. Ves• Fibres non-libriform, non-septate, angular sels distinct with the naked eye, orifices in shape, walls 2-3 f1. thick, 330-1200 [1. long, visible as pin-pricks, medium-sized to large, 20-30 [1. in diameter; interfibre pits not the majority solitary but also in short radial preserved. rows of 2-4 (mostly 2) (PL. 2, FIG 8), con• Affinities - The most important ana• tiguous with the rays on one or both the tomical feature of the fossil wood is the sides; tyloses abundant (PI.. 3, FIG. 15), presence of normal gum-canals in the fusi• occluding many vessels, deposits of reddish• form rays. Among the dicotyledons there brown colour probably gum occasional in are only 24 families and about 152 genera the tyloses; 2-9 per sq. mm. Parenchyma which possess normal horizontal gum-canals 26 THE PALAEOBOTANIST

TEXT-FIG. 4 - Swintonioxyloll hailahandiense Prakash & Tripathi. Cross-section showing the distribution of parenchyma (pf. X 33. (Slide No. 3266).

in the xylem rays (METCALFE & CHALK, genera of the family Anacardiaceae onlv 1950, pp. 1353-1354). These are as about 33 show normal horizontal gum• follows: canals (ANONYMOUS, 1963; METCALFE & Anacardiaceae, Apocynaceae, Araliaceae, CHALK, 1950, p. 1353) in the xylem rays. Out Burseraceae, Cactaceae, Cochlospermaceae, of these, only nine Indian genera possess Composi ta e, Crypteroniaceae, Dipterocarpa• these gum-canals. These are Buchanania, ceae, Euphorbiaceae, Guttiferae, Hamarneli• Gluta, Lannea, Parishia, Pistacia, 111agnifera daceae, Julianiaceae, Loganiaceae, Moraceae, longipes, Rhus, Spondias and Swintonia Myrtaceae, Rosaceae, Rubiaceae, Rutaceae, (ANONYMOUS, 1963, p. 266; PEARSON & Sapindaceae, Solanaceae, Thymelaeaceae, BROWN, 1932, p. 310). On an extensive Ulmaceae, Umbelliferae. study of the thin sections of modern woods Besides the presence of normal gum• of these genera, it has been found that the canals in the fusiform rays, the fossil also fossil wood indicates its closest affinitv to shows some other important anatomical the modern genus S"liJintonia Griff. Thin features. These are the presence of large sections of the species S. griffithii Kurz, pores (Ld. 100-288 [J.) profusely occluded with S. helferi Hook., and S. jloribunda Griff. tyloses, continuous or broken tangential syn. S. schwenckii (Teysm. et Binnend.) bands of parenchyma, 1-3 (mostly 2) seriate, Kurz, were examined in detail besides heterocellular normal xylem rays and thin• studying published description and photo• walled, non-septate fibres. graphs of S. jloribunda Griff. (PEARSON All the above important anatomical fea• & BROWN, 1932, pp. 333-335, FIG. 120; tures indicate the affinity of the fossil wood HENDERSON, 1953, p. 9, FIG. 8; HEIMSCH, with the family Anacardiaceae (METCALFE 1942, PL. 11, FIG. 65), S. grijjithii Kurz & CHALK, 1950; ANONYMOUS,1963; DESCH, (METCALFE & CHALK, 1950, p. 457), S. 1957; PEARSON & BROWN, 1932; HEIMSCH, penangiana King, S. spic1fera Hook., S. 1942; RECORD, 1925). Out of about 65 jloribunda Griff. (DESCH, 1957, pp. 12-14), PRAKASH & TRIPATHI - FOSSIL WOODS OF LEGUMINOSAE AND ANACARDIACEAE 27

S. speciJera Hook. (HENDERSON, 1953, near Pondichcrry (M. sclcroticwm Awasthi, p. 9, FIG. 9) and Swintonia sp. (CHOWDHURY, 1966). From outside India, a number of 1936). fossil woods belonging to the family Anacar• A detailed examination of all the impor• diaceae are known (EDWARDS,1931; ED• tant anatomical features indicates that WARDS & WONNACOTT,] 935; ANDREWS, the fossil wood resembles more closely the 1955; BOrREAU, 1957, pp. 668-669) but species Swintonia jloribunda Griff. syn. S. these as well as those from India differ schwenckii, (Teysm. et Binnend.) Kurz widely from the present fossil wood. (F.R.I. slide no. 379/E 6068). The present The genus Swintonia, Griff. consists of fossil wood resembles the modern wood of S. about 8 species (WILLIS, 1957) of tall ever• jloribunda in shape, size and distributional green trees. It is confined in the Old World pattern of the vessels, in the nature of inter• and strictly Indo-Malayan in distribution. vascular pitting, in parenchyma distribution It occurs in East Pakistan, Burma and the and the fibre and ray structure. However, Malay Peninsula extending to the Philip• the fossil wood differs from S. jloribunda pine Islands. Two species grow in Burma, in having very broad xylem rays with trau• one of which extends to ChiUagong in East matic gum-canals and the crystalliferous Pakistan (PEARSONW BROWN,1932, p. 333; ray cells. These are not very reliable char• ANONYMOUS,1963). The species S. jlori• fcters; the traumatic gum-canals may be bUnda syn. S. schwenkii with which our 'Bormed dne to injury in any part of a plant. fossil wood shows nearest resemblance is Similarly, the crystals are sometimes present represented in the modern flora of East in some specimens of a plan t while absen t Pakistan, about a distance of 288 kms. in others. from the Jossil locality. It is a tall tree Since the present fossil wood shows clos• with cylindrical bole and grows in Chitta• est resemblance with the wood structure gong and Burma, along rivers and in tropical of Swintonia, it has been designated as forests. In Chittagong forests, this is one Swintonioxvlon Prakash & Tripathi. It is of the most conspicuous trees, especially specifically named as S. haliakandiense along the banks of the Karanfuli river after the name of the locality Haila• (GAMBLE,1902, p. 2]8). kandi from where the fossil wood has been collected. As far as we are aware, there is no record DIAGNOSIS of fossil Swintonia from India and abroad and this forms the first record of the fossil Swintonioxylon Prakash & Tripathi wood of Swintonia from the Tertiary of Assam. Wood diffuse-porous. Growth rings dis• So far only three genera of Anacardiaceae tinct or indistinct. Vessels large to medium• are represented by the fossil woods from sized, majority solitary or in short radial the Tertiarv of India and Burma. These rows, round to oval, profusely tylosed, are Glutoxylon Chowdhury (1934) from the with deposits of reddish-brown probably Tertiary rocks of Bengal (Glutoxylon sp. gum occasional in the tyloses; vessel-mem• MUK.HERJEE, 1942a; G. bengalensis Mu• bers with truncate or tailed ends; per• KHERJEE,1942b, 1942c; G. burrnense (Hold.) forations simple; intervessel pit-pairs large, CHOWDHURYby CHOWDHURY& TANADN, bordered, oval 1.0 angular through crowding 1952), Manipur (G. chowdhuri GHOSH,1958), with lenticular orifices. Parenchyma para• Tripura (G. burrnense (Hold.) CHOWDHURY tracheal and apotracheal; paratracheal by GHOSH& TANEJA, 1961), Assam and parenchyma vasicentric, aliform and aliform• Burma (G. burrnense (Hold.) CHOWDHURY, confluent; apotracheal parenchyma in long 1950, 1952), South India near Pondicherry and short bands. Xylem rays both fine (G. cuddalorense AWASTHI,1966), Anacar• and fusiform containing gum-canals; ray dioxylon Felix (1882) from the Deccan tissue heterogeneous; rays heterocellular Intertrappean series (A. sernecarpoides composed of procumbent cells in the middle PRAKASH & DAYAL, 1965) and the Mio• portion and upright cells at one or both Pliocene of Cuddalore Series near Mortandra the ends; fusiform rays with radial gum in South India (A. mangijeroides RAMANU• canals. Fibres non-libriform, non-septate, JAM, 1960) and Mangijeroxylon Awasthi with big lumina. Intercellular canals, hori• (1966) from the Tertiary of South India zontal, confined to the rays. 28 TIlE PALAEOBOTANIST

Swintonioxylon haila/?andiense Prakash & large, solitary as well as in radial multiples Tripathi of 2-4, evenly dist.ributed, 7-11 per sq. mm., heavily occuluded with tyloses (PL. 3, FIG. Wood diffuse-porous. Growth rings indis• 17). Parenchyma scanty, paratracheal, not tinct. Vessels large to medium-sized, t.d. visible with the hand lens, difficult to locate 100-2·88 fL, r.d. 110-320 fL, majority solitary even under the microscope, occurring as but also in short radial rows of 2-4, thin• few cells about the vessels (PL. 4, FIG. 21). walled, profusely tylosed, with deposits of Xylem rays not visible to the naked eye, reddish-brown probably gum occasional in distinct with a hand lens on the cross-sur• the tyloses, 2-9 per sq. mm.; vessel-members face of the wood, fine to moderately broad, short to medium-sized, 220-700 fL long with rarely with gum canals, 1-7 (mostly 3-4) truncate or tailed ends; perforations simple; seriate (PL. 3, FIG. 19) and 20-84 fL broad, inter-vessel pit-pairs large, 8-12 fL in dia• 3-32 cells or 160-720 fL high; rays 6-8 per meter, bordered, oval to angular through mm.; ray tissue het.erogeneous; rays hetero• crowding. Parenchyma paratracheal and cellular consisting of procumbent cells in apotracheal; paratracheal parenchyma vasi• the middle portion and 1-2 rows of upright centric, aliform and aliform-confluent; apo• cells at one or both the ends (PL. 3, FIG. 19). tracheal parenchyma in short and long Fibres aligned in more or less distinct radial bands. Xylem rays both fine and fusiform; rows between the two consecutive xylem fine rays 1-3 (mostly 2) seriate and 15-90 rays. Intercellular canals horizontal, nor• fL broad, 2-23 cells and 90-1200 fL high; mal, confined to the xylem rays, 25-35 fL fusiform rays both with normal and trau• in diameter (PL. 4, FIG. 23). matic gum canals; rays with normal gum• Elements - Vessels thin-walled, walls canals occasional, 6-12 seriate, but those 4-8 fL thick, t.d. 75J230 fL, r.d. 120-340 fL, with traumatic gum canals quite frequent, the solitarv vessels round to oval in cross• 15-32 seriate; rays 14-18 per mm.; ray tissue section, s~1l1etimes elliptical due to com• heterogeneous; rays heterocellular composed pression_during fossilization, those in radial of procumbent cells in the median thicken• multiples flattened at the places of contact; ed portion and upright cells at one or vessel-members 180-360 fL long, truncate both the ends. Fibres non-libriform, non• or with tailed ends; perforations could not septate~ thin walled, angular in cross-section, be seen; intervessel pit-pairs large, 10-12 330-1200 fL long and 20-30 fL in diameter. fL in diameter, bordered, alternate, border I ntercellular canals horizontal in xylem rays, oval and angular due to crowding with both normal and traumatic; normal canals linear-lenticular orifices (PL. 4, FIG. 22); 45 fL and traumatic canals 195-255 fL in vessel-parenchyma and vessel-ray pits not diameter. observed. Parenchyma cells thin-walled, Holotype - B.S.I.P. Museum No. 33749. peripherally flattened in cross-section, 80• Locality - Hailakandi, district Cachar, 220 fL in length and 12-20 fL in diameter. Assam. Ray cells thin-walled occasionally crystalli• Horizon - Probably Tipam series. ferous; tangential length of procumbent Age - Tertiary (Middle Miocene). cells 20-32 fL, radial length 80-140 fL; upright cells 32-64 fL in tangential and 24-48 fL in Lanneoxylon Prakash & Tripathi, 1967 radial length. Fibres moderately thick• walled with big lumina, walls 2-4 fL thick, Lanneoxylongrandiosum Prakash & Tripathi, septate, angular in cross-section, 300-1500 1967 fL long, 25-40 fL in diameter; interfibre pits not preserved. The material on which the present study Affinities - The most important ana• is based, comprises a pertified piece of de• tomical feature of the present fossil wood corticated secondary wood. It is about is the presence of normal, horizontal gum 4·5 cm. in length and 3·5 cm. in diameter.' canals in the xylem rays. Among the It is brown in colour with fairly good pre• dicotyledons, there are only 24 families servation. and about 152 genera in which the normal, Topography - Wood diffuse-porous (PL. horizon tal gum canals are found (METCALFE 3, FIG. 17). Growth rin{!s indistinct. Ves• & CHALK, 1950; RECORD, 1925). Besides sels appearing as minute dots with the naked the presence of normal gum canals in the eye on the cross-surface, small to moderately xylem rays, the fossil wood also shows small PRAKASH & TRIPATHI - FOSSIL \'\TOODSOF LEGUl\1:INOSAE AND ANACARDIACEAE 29 to moderately large pores (t.d. 750 [1--23) frequent than the present fossil wood (PEAR• profusely occuluded with tyloses; alternate, SON & BROWN, 1932,pp. 218-220). However, bordered, inter-vessel pits; scanty para• it is with the wood structure of Lannea A. tracheal parenchyma; 1-7 (mostly 3-4) Rich, especially L. coromandelica (Houtt.) seriate, hetrocellular xylem rays with 1-2 Merr. [syn.Lanneagrandis (Dennst.) Engler, rows of upright cells; and moderately thick• Odina wodier Roxb., L. Wodier (Roxb.) walled, septate fibres. Considering all the AdelbJ (RAIZADA, 1958 p. 491) that the features collectively some genera of the fossil wood shows closest affinities. Besides families Burseraceae and Anacardiaceae examining the modern wood slides of L. show greater resemblance with the present coromandelica and L. acidissima the pub• fossil wood. lished describtion and photographs of In the family Burseraceae, there are Lannea welwitschii Engl. (KRIBS, 1959, p. 8, about nine genera in which radial gum FIG. 336; NORMAND, 1955, PL. 89); L. canals are found in the xylem rays. Among acidissima A. Chev. (METCALFE & CHALK, the Indian genera, radial gum canals which 1950, FIG. 103 J); L. barteri Engl. (MET• are occasionally visible under hand lens CALFE & CHALK, 1950) and L. coyomandelica have been observed in Balsamodendron, syn. Odina wodier (MOLL & jANSSONIUS, Boswellia and Car~tga (ANNONYMOUS,1963, 1908, FIG. HI ; CHOWDHURY,1943; PEARSON pp. 64-80; MOLL & jANSSONIUS, 1908, pp. & BROWN, 1932) were also consulted. 87-109; PEARSON & BROWN, 1932, pp. 217• The size, shape and distribution of vessels 233; HEIMSCH, 1942, pp. 122-124; METCALFE in the present fossil wood is similar to the & CHALK, 1950, pp.345-347; RECORD, 1925, distributional pattern in the modern species, pp. 19-20). Of these only two genera Caruga Lannea coromandelica (Houtt.) Merr. Both and Boswellia are worth comparing. in the fossil and the living species, the vessels Similarly in the family Anacardiaceae, are small to moderately large, solitary as there are number of genera which are char• well as in radial multiples of 2-4 and the acterized by the presence of radial gum intervessel pit-pairs are large, alternate, canals (ANNONYMOUS,1963; RECORD, 1925; bordered with linear-linticular apertures. 1939; MOLL & jANSSONIUS, 1908; PEARSO The amount and distribution of the paren• & BROWN, 1932; DESCH, 1957; HEIMSCH, chyma as also the nature and distribution 1942; METCALFE& CHALK, 1950). Amongst of the xylem rays, the presence of radial these, the Indian genera with radial gum canals and the type of fibres are basically canals are Buchanania, Cluta, Lannea, Pari• similar in both the fossil and the modern shia, Pistacia, Mangifera (only M. longipes), wood of L. coromandelica (Houtt.) Merr. Rhus, Spondias and Swintonia among which So far only three genera of the family Lannea is remarkably close to the fossil Anacardiaceae are represented by fossil wood. woods from the Tertiary of India. Recent• Considering the wood structure of the ly, a fossil wood of Swintonia, Swintoni• genera Caruga, Boswellia and Lannea for oxylon haliahandiense Prakash & Tripathi detailed comparison, it appears that the (1968) has also been recorded from Haila• genus Boswellia is nearer in structural de• kandi, district Cachar, Assam. From out• tails to the fossii wood than Caruga. The side India, a number of fossil woods be• wood of Caruga can be distinguished from longing to the family Anacardiaceae are the present fossil wood in possessing larger known but these as well as those from pores and rays with enlarged end cells con• India differ widely from the present fossil taining crystals. Caruga pinnata, the only wood. Indian species, can be further separated As far as we are aware there is no authentic by the presence of large and frequent radial record of fossil Lannea from India and ab• gum canals (PL. 4, FIGS. 26 & 27). It may road and this forms the first record of the be mentioned here that in C. jloribunda fossil wood of Lannea from the Tertiary of described and figured by Reyes (1938, pp. Assam. However, Krausel (1922) described 164, 165, PL. 25, FIG. 2) the intercellular Anacardioxylon mollii from the Tertiary of radial canals are absent and the rays have South Sumatra which he compared with oil-cells. Boswellia also differs from the Odina wodier syn. Lannea coromandelica. fossil wood in having xylem rays without Den Berger (1923) compared A. mollii with the crystals (PL. 4, FIGS. 24, 25) and the the members of the family Burseraceae and radial gum canals being larger and more gave it a non-committal name Sumatroxylon jo 'tHE PALAEOBOTANlST mollii. However, the affinities of this fossil thick-walled with big lumina, septate. wood are still uncertain. Intercellular canals horizontal, confined to Since the present fossil wood shows closest some xylem rays. resemblance with the wood structure of Lannea it has been assigned to Lanneoxylon Lanneoxylon grandiosum Prakash & Tripathi Prakash & Tripathi. It is specifically nam• ed as L. grandiosum as it is closely allied to Wood diffuse-porous. Growth rings indis• the wood structure of the modern Lannea tinct. VesseZs small to moderately large, grandis. t.d. 75-230 fl, r.d. 120-340 fl, solitary as The genus Lannea A. Rich, consists of well as in radial multiples of 2-4, thin-walled, about 15 species of small to large deciduous heavily tylosecl, 7-11 per sq. mm.; vessel• trees distributed in tropical Africa and members short to medium-sized, 180-360 fl Asia. The only species found in the Indian long, with truncate or tailed ends; perfora• region is Lannea coromandelica syn. Lannea tions simple; intervessel pit-pairs large, grandis Engl. The tree has a wide distl-i• 10-12 r in diameter, bordered, oval to angu• bution in India and is found in the dry lar, with linear-lenticular anertures. Pa• forests of all states except parts of Punjab, renchyma scanty para tracheaL Xylem rays Rajasthan and Saurashtra. It is found fine to moderately broad with gum-canals in the sub-Himalayan tract and the lower in some, 1-7 (mostly 3-4) seriate and Himalayas from the Indus eastwards as• 20-8'} fl broad, 3-32 cells or 160-720 fl high; cending to 1,200 m., common in Siwaliks, rays 6-8 per mm.; ray tissue heterogeneous, Dehradun and Saharan pur forests, also rays heterocellular composed of procumbent throughout the area of Pilibhit, Oudh, cells through the median thickened portion Gorakhpur and Bundelkhand of Uttar Pra• and upright cells at one or both the ends; desh but not so common in Bengal and cells sometimes crystalliferous. Fibres Assam and scattered in Bihar and Orissa. moderately thick-walled with big lumina, It is also common in Khandesh and Deccan walls 2-4 (.I. thick, septate, angular in cross• forests, very common in Travancore and section, 300-1500 fl long and 25-40 fl in in the decidous forest of Mysore and Madras. diameter. Intercellular canals horizontal, In the Andamans the tree grows frequently normal confined to some xylem rays, 25-35 in damp places along streams. It occurs (.I. in diameter. also in Burma and Ceylon (ANONYl\lOUS, Holotype - B.S.I.P. Museum no. 33792. 1963). Locality - Road cutting at mile-stone 9 on Dimapur-Diphu road in Mikir Hills, DIAGNOSIS Assam. Horizon - Probably Tipam series. Lanneoxylon Prakash & Tripathi Age - Tertiary, probably Mi~dle Miocene. Wood diffuse-porous. Growth rings want• ACKNOWLEDGEMENTS ing or scarcely distinct. Vessels small to large, solitary or in radial multiples, Thanks are due to Mr. A.N. Dutta, Vijnan round to oval, tylosed;. vessel-members Mandir OfficerHailakandi, Assam, for kindly with truncate or tailed ends; perforations sending us the fossil wood specimens from simple; intervesse1 pit-pairs large, bordered, near Hailakandi for investigation. We are oval or angular where crowded with linear• also indebted to Mr. K. Ramesh Rao, Officer• lenticular orifices. Parenchyma scanty para• in-Charge, \Vood Anatomy Branch, Forest tracheal. Xylem rays fine to moderately Research Institute, Dehra Dhun, for the broad; ray tissue heterogeneous, rays facilities to consult the Xylarium of the heterocellular. Fibr.:s thin to moderately Institute and for the help in many ways.

REFERENCES

ANDREWS (Jr.), H. N. (1955). Index of Generic AWASTHI,N. (1966). Fossil woocs of Anacardiaceae names of fossil plants. 1820-1950. Geal. Surv. from the Tertiary of South India. Palaeabalanisl. Bull. Wash. 1013: 1-262. 14 (1-3): 131-143 (1965). Anonymous (1963). Indian ·Woods. 2. Dehra BERGER, L. G. DEN (1923). Fossil Houtsoorten Dun. uit het Tertiar van Zuid - Sumatra. Verhand. PRAKASH & TRIPATHI -I'OSSIL WOODS OF Lf:GUlYIlNOSAE AND ANACARDIACEAE 3i

Geol. Mijnb. Gen. Nederland en Kol. 7: 143• KANEHIRA, R. (1924). Identification of Philippine 148. woods by anatomical characters. Govt. Res. BOUREAU, E. (1957). Anatomie Vegetale L'ap• Inst. Taihoku, Formosa: 1-73. pareil Vegetatif des Phanerogames. 3. Paris. KRIBS, D. A. (1959). Commercial foreign woods CHOWDHURY,K. A. (1934). A fossil dicotvledonous on the American market. Pe.nnsylvania. wood from Assam. Curro Sci. 3(6): 255-256. KRAUSEL, R. (1922). Beii.rage zur Geologic und Idem (1936). A fossil dicotyledonous wood from Palaontologie von Sumatra. Fossile Holzer Assam. Ann. Bot. Lond. 50(199): 501-510. aus dem Tertiar von sud-Sumatra. Verltand. Idem (1938). Two fossil dicotyledonous woods geol. Mijnb. Gen. lI'ederland en Kol. 5: 231-287. from the Garo I-hils, Assam. Rec. geol. Surv. LAKHANPAL, R. N. (1952). Nipa sahnii, a palm India. 73: 247-266. fruit in the Tertiary of Assam. Palaeobotanist. Idem (1943). How to identify Timbers. Pt. 4. 1: 289-294. Indian For. Leaflet. 46: 30-59. 1dem (1955a). Recognisable species of Tertiary Idem (1950). Assam, Nowgong district Fossil plants from Damalgiri in the Garo Hills, Assam. wood (Glutoxylon) from Assam. Palaeobot. Ibid. 3: 27-31 (1954). India. 7. j. Indian bot. Soc., 29(1): 34. Idem (1955b). On the occurrence of Nelumbium Idem (1952). Some more fossil woods of Glutoxylon from the Tertiary of Assam. j. Indian bot. from South-east Asia. Ann. Bot. N.S. 16(63): Soc. 34(3): 222·224. 373-378. METCALFE,C. R. & CHALK, L. (1950). Anatomy of CHOWDHURY,IC A. & GHOSH, S. S. (1946). On the the Dicotyledons. 1 & 2. Oxford. anatomy of Cynometroxylon indicum gen. et MOLL, J. W. & J ANSSONIUS,H. H. (1908). Mikro• sp. novo A fossil dicotyledonous wood from graphie des holzes del' auf Java Vorkommenden Nailalung, Assam. Proc. Indian. Inst. Sci. I. Baumarten. 2. Leiden. 12(8): 435-447. Idem (1914). Mikrographie des Holzes der auf CHOWDHURY, K. A. & TANDAN, K. N. (1949). Java Vorkommenden Baumarten. 3. Leiden. Kayeoxylon assamicum gen. et sp. nov., a MUKHERJEE, A. (1942a). Identification of fossil fossil dicotyledonous wood from Assam. Ibid. wood from the Lalmai Range in Comilla, Bengal. 15(2): 59-65. Sci. & Cull. 7(11): 572-574. Idem (1952). A new record for the fossil wood Idem (1942b). A fossil dicotyledonous wood from Glutoxylon from the southern part of West Mainamati hills. Ibid. 7(7): 370-371. Bengal. Curro Sci. 21 (6); 161. Idem (1942c). A fossil dicotyledonous from Maina• DAS GUPTA, A. B., EVANS, P., METRE, A. K. & mati hills in Tipperah district, Bengal. Q. J. VISVANATH,S. N. (1964). Tertiary Geology and geol. Min. metall. Soc. India. 14(2): 75-82. oil fields of Assam. Guide to excursion nos. NORMAND, D. (1955). Atlas des bios de la cote A-17 & C-14. Int. geol. Congo 22nd Session, D'h-oire. 2. Nogent-Sur-Marne, Seine. India. 1964 - New Delhi. PEARSON, R. S. & BROWN, H. P. (1932). Commer• DESCH, H. E. (1957). Manual of Malayan Timbers. cial timbers of India. 1. Calcutta. Malayan Forest Records No. 15, Vol. 1: 1-328. PRAKASH, U. (1966). Fossil wood of Cassia and EDWARDS, W. N. (1931). Fossilium Catalogus 11. Cynornetra. from the Tertiary beds of Mikir Hills, Plantae, Dicotyledones (Ligna). 17: 1-96. .\ssam. 'Centre of Advanced study in Geology', EDWARDS, W. N. et WONNACOT, F. M. (1935). Punjab University, Cltandigarlt, Pub. no. 3: 93·100. Fossilium Catalogus II: Plantae, Anacardiaceae. PRAKASH, U. & DAYAL, R. (1965). Fossil wood 20: 1-73. resembling Semecarpus from the Deccan Inter• EVANS, P. (1932). Explanatory notes to accom• trappean beds of Mahurzari near Nagpur. pany a table showing the Tertiary succession in Palaeobolanist. 13(2): 158-162 (1964). Assam. Trans. Min. geol. Inst. India. 27: PRAKASH,U. & NAVALE, G. K. B. (1963). Termi· 155-260. nalioxylon cltowdlturii sp. nov., A new fossil EYDE R. H. (1963). A Shoreoxylon and other dicotyledonous wood from the Tertiary rocks Tertiary woods from the Garo Hills, Assam. of Assam. Ibid. 11(1, 2): 49-53 (1962). Palaeobotanist. 11(1, 2): 115-121 (1962). PRAKASH, U. & TRIPATHI, P. P. (1967). Fossil FELIX, J. (1882). Studien tiber fossile Holzer. wood of Lannea from the Tertiary of Assam. Inaug. Diss. Leipzig: 1-81. Curro Sci. 36(17): 462-463. GAMBLE,J. S. (1902). A manual of Indian Timbers. Idem (1968). Fossil wood of A denantltera and London. Swintonia from thc Tertiary of Assam. Ibid. GHOSH, S. S. (1956). On a fossil wood bclonging 37(4): 115-116. to the genus Dipterocarpus. Sci. & Cult. 21: RAIZADA,M. B. (1958). Name changcs in common 691-692. Indian plants. 1ndian Forester: 467-538. Idem (1958). A new record for the fossil wood RAMANUJAi\I, C. G. K (1960). Silicificd woods Glutoxylon from Manipur. Ibid. 23: 431-433. from the Tertiary rocks of South India. Palaeon• GHOSH, S. S. & TANEJA, K. K. (1961). Further tographica. 106B: 99·140. record of Glutoxylon from the Miocene (?) of RECORD, S. J. (1925). Occurrence of intercellular Tripura. Ibid. 27: 581-582. canals in dicotyledonous woods. Trop. Woods. HEIMSCH, C. (Jr.) (1942). Comparative anatomy 4: 17-20. of the secondary xylem in the "Gruinales" Idem (1939). American woods of the family Ana• and "Terebinthales" of \"Iettstein with refe• cardiaceae. Ibid. 60: 11-45. rence to taxonomic grouping. Lilloa. 8: 83-198. REYES, L. J. (1938). Philippinc woods. Tech. HENDERSON, F. Y. (1953). An Atlas of end-grain Bull. Dept. Phil. 7: 1-450. photomicrographs for the identification of hard TROUP, R. S. (1921). The Silviculture of Indian woods. Forest Products Res. Bull. 26. London. Trees. 2. Oxford. HOOKER, J. D. (1879). The flora of British India. WILLIS, J. C. (1957). A Dictionary of the Flowering 2. Kent, England. plants and ferns. Cambridge. 32 TRE PALAEOBOTANIST

EXPLANATION OF PLATES

PLALE 1 PLATE 3 1. Cross-section of the fossil wood of Adenanthero• 15. Cross-section of the fossil wood of S. xylon pavoninium showing vessel distribution and hailakandiense magnified to show the aliform and the parenchyma pattern. x 30. (Slide No. 3262). banded parenchyma. X 100. (Slide No. 3266). 2. Cross-section of Adenanthera pavonina Linn. 16. Radial section of the fossil wood of S. showing similar vessel distribution and the paren• hailakandiense showing the heterogeneous xylem chyma pattern. X 30. rays. X 90. (Slide No. 3269). 3. Tangential section of the fossil wood of A. 17. Cross-section of the fossil wood of Lan• pavoninium showing the type of xylem rays and neoxylon grandiosum showing vessel distribution. their distribution. x 90. (Slide No. 3263). X 43. (Slide No. 3270). 4. Tangential section of Adenanthera pavonilla 18. Cross-section of the modern wood of Lannea Linn. showing similar ray type and their distri• coromandelica (Routt.) Merr., showing similar vessel bution. X 90. distribution. X 43. 5. Cross-section of the fossil wood of A. pavonin• 19. Tangential section of the fossil wood of L. ium magnified to show the shape of the vessel and grandiosum showing the type of xylem rays and paratracheal parenchyma. X 80. (Slide No. 3262). their distribution. X 60. (Slide No. 3271). 6. Tangential section of the fos~il wood of A. 20. Tangential section of the modern wood of pavininium magnified to show intervessel pits. Lannea coromandelica (Routt.) Merr., showing X 190. (Slide No. 3264). similar ray type and their distribution. X 60. 7. Raclial section of A. pavoninium showing the homogeneous xylem rays. X 130. (Slide No. 3265). PLATE 4 PLATE 2 21. Cross-section of thc fossil wood of L. 8. Cross-section of the fossil wood of Swintonio• grandiosum magnified to show scanty para tracheal xylon hailakandiense showing vessel and paren• parenchyma. X 80. (Slide No. 3270). chyma distribution. X 30. (Slide No. 3266). 22. Magnified intervascular pitting of L. grandio• 9. Cross-section of Swintonia jloribunda Griff. sum. X 850. (Slide No. 3271). showing similar vessel and parenchyma distribution. 23. Tangential section of the fossil wood of L. X 30. grandiosum showing gum-cunal in a xylem ray. X 10. Tangential section of the fossil wood of S. 75. (Slide No. 3272). hailakandiense showing xylem rays and their distri• 24. Cross-section of the modern wood of Boswellia bution. X 110. (Slide No. 3267). serrata Roxb. showing vessel and parenchyma 11. Tangential section of Swintonia jloribunda distribution. X 43. Griff. showing the similar xylem rays and their 25. Tangential section of the modern wood of distribution. X 110. Boswellia serrata Roxb. showing the xylem rays. 12. Tangential section of the fossil wood of S. X 60. hailakandiense showing traumatic gum-canals in 26. Cross-section of the modern wooel of Garuga the xylem rays. X 40. (Slide No. 3267). pinnata Roxb. showing vessel and parenchyma 13. Tangential section of the fossil wood of S. distribution. X 43. hailakandiense showing a normal gum-canal in the 27. Tangential section of the modern wood of xylem rays. X 40. (Slide o. 3268). Garuga pinnata Roxb. showing the xylem rays 14. Magnified intervascular pitting of S. with enlarged end cells containing crystals and a hailakandiense. X 410. (Slide No. 3267). ray with a gum-canal. X 60. THE PALAEOBOTANIST, VOL. 17 PRAKASH & TRIPATHI - PLATE 1 PRAKASH & TRIPATHI - PLATE 2 THE PALAEOBOTANIST, VOL. 17 PRAKASH & TRIPATHI-PLATE 3 THE PALAEOBOTANIST, VOL. 17

20 PRAKASH & TRJPATHI-PLATE 4 fH.E PALA·EOBOTAl'J~T, VOL. 17