BOT, SURV. BULL. -- Val. 11, Nos. 3 8 4 : pp. 286-289, 1968

EPIDERMAL AND VENATION STUDIES IN -I

National Botanu Gmdm, Lucknow

ABSTRACT Epidermal characters and venation pattern of the of six arboreal s ecies of Apocynaceae, viz., Ahtonin mamophylla Wall. ex DC., Holarrhena antidyzcnttrica Wall., a Pba Linn., P. rubra Linn. forma acuminata Sant. & Irani ex Shah, tinctoria R. Br. and W.tomntosa Roem. & Schult. have been described.

INTRODUCTION and marginal parts). These were cleared with The needs of modern taxonomy are not fully met chloral-hydrate, stained with safranin and mounted merely by gross morphology. A taxonomist these in glycerine. The slides were ringed with Canada days applies more and more data collected from balsam. various fields of botany for a better comprehension of the taxon under study. In numerical taxonomy OBSERVATIONS too a large number of characters is needed for The macro-characters of the leaves as available in computation, for a reliable evaluation of the various floras need to be supplemented. A detailed measure of affinity (Sokal & Sneath, 1963). As a account of the same is also given below alongwith matter of natural course this has led to increased. the micro-characters. research in the related fields of botany such as cyto- logy, embryology, serum analysis etc., with the aim: Alstonia macrophyUa Wall. ex DC. of amassing a wealth of data concerning each indi- Macro-characters: Leaves verticillate, 3-4 at each vidual species. node, simple, petiolate ; ~etiolestout, upto 2 cm The significance of epidermal morphology and long, pubescent ; lamina oblanceolate or elliptic- venation pattern as a helpful tool in phylogenetic lanceolate, shortly caudate, obtuse or somewhat and taxonomic considerations needs no emphasiz- acute, base cuneate and slightly decurrent, upto gr ing (Florin, 1931 ; Harris, 1942-43, Foster & Gifford, cm x ro cm, entire, coriaceo-chartaceous, upper sur- 1959, etc.). Further, these characters can at times face shining bright green, glabrous or sparsely pube be of immense value in identifying crude drugs. rulus, lower surface rather paler, pubescent mainly on Impressed by these considerations the authors the main nerves otherwise sparsely puberulus, nerva- have taken up the epidermal and venation studies tion conspicuous, nerves 16-25 pairs, spreading, mid- in family Apocynaceae. The present communica- rib and lateral nerves prominently raised beneath. tion being first of the series deals with six arboreal Micro-characters : Epidermal cells usually penta- sppcies, viz., A Zstoni~ mncrophylla, Holrrrrhena or hexa-gonal, upper straight walled, lower slightly antidy senterica, Plumria atba, P. ru bra forma sinuate. Stomata confined to tower surface o~dy, acuminata, IVrightia tinctoria and W. tornentosa. 20 x 13.7~(average), usually rubiaceous, rarely ranun- MATERIAL AND METHODS culaceous; stomata1 index 15-18-22. Trichornes Material investigated, consisted of normal and simple, unicellular, unbranched. Vein islets 26 mature leaves collected in the month of June from (average) per sq. mm. vein endings 21 (average) per the trees growing at Lucknow. Fresh leaves were sq. mm. kept in 10% Nitric acid for 24-48 hours. These were then washed in water and the epidermal peel- Holmhem antidy-terica Wall. ings were taken. These were stained with Macrocharacters : Leaves opposite, simple, nearly Delafield's haematoxylin and mounted in 50% sessile or petiolate ; petiole up to 2 cm long, pubes- glycerine. For the study of venation pattern, cent ; lamina broadly ovate or elliptic-oblong, shortly small ~ieces(squarish in shape) were cut out from, caudate, acute or acuminate, base rounded or broad. the central part of the leaves (excluding midrib ly cuneate, slightly decurrent, upto 28 cmx ro cm, 19691 CHANDRA et at.: EPIDERMAL AND VENATION STUDIES IN APOCYNACEAE-I 287 entire, chartaceous, upper surface shining bright marginal vein, midrib and lateral nerves promi- green, nearly glabrous or sparsely puberulus, lower nently raised beneath. surface rather paler, softly pubescent on the nerves Mzcro-characters : Epidermal cells penta- or hexa- otherwise puberulus, nerve pattern conspicuous, gonal, upper as well as lower straight walled. main lateral nerves 5 to 15 pairs, arcuate, promi- Stomata present on both the surfaces, rubiaceous, nently raised beneath. upper 33 x 22~,lower 25.3 x 19p ; stornatal index Micro-characters : Epidermal cells penta- or 3-44 (upper surface) and I 1-14-2I (lower surface). hexa-gonal, upper straight walled, lower sinuate. Trichomes simple, unicellular, unbranched. Vein Stomata confined to lower surface only, 21 X 15p islets 11 (average) per sq. mm. Vein endings 19 (average), usually rubiaceous, rarely ranunculacesus; (average) per sq. mm. stomatal index [(FI 2-16. Trichornes simple, uni- cellular, unbranched. Vein islets 8 (average) per Wrightia Linetoria R. Br. sq. mm. Vein endings rg (average) per sq. mm. Macroeharacters : Leaves opposite, simple, aE most sessile or shortly pefiolate; petiole upto 0.3 cm Plmeria alba Linn. long, glabrous; lamina elliptic-ovate or elliptic-oh- Macrocharacters : Leaves alternate, crowded to- long or elliptic-lanceolate, caudate-acute or- acu- wards the end of the branches, simple, petiolate ; minate or shortly acuminate, base may or may not petiole upto 8 cm long, pubescent ; lamina oblong, be oblique, rounded or slightly cuneate, upto oblong-oblanceolate or oblong-obovate, obtuse or 18 cmx8 ctn (upto 25 c.m xg cm on new branches retuse or mucronately toothed, base cuneate, slightly coming out from the main bole of the tree near the decurrent, upto 35 cm x r 1.5 cm entire, thickly coria- base), entire, firmly chartaceous, upper surface ceous, upper surface shining dark green, glabrous, bright green, glabrous, lower surface pale green, somewhat rugose, lower surface lighter, densely glabrous, nervation conspicuous, main lateral nerves pubescent particularly on the main nerves, nervation 6-15 pairs, nerves and nervules raised beneath. conspicuous, lateral nerves 15-35 pairs, almost parallel Micro-characters : Epidermal cells penta- or ultimately uniting into an intramarginal one, all hexa-gonal, upper straight walled, lower slightly these and even the tertiaries prominently raised sinuate. Stomata frequent on lower surface and beneath. rare on upper, lower 23.3 x 18.7 p (average) and upper Macro-characters : Epidermal cells penta- or hexa- 29 x 25.7 p (average), rubiaceous ; stomatal index gonal, upper straight walled, lower almost straight I 8-2 1-24 (lower surface). Trichomes absent. Veht walled. Stomata confined to lower surface only, &lets 20 (average) per sq. mm. Vein endings 38 x 16.7 p (average), rubiaceous ; stomatal index 33 (average) per sq. mm. 16-2~24. Trichomes confined to lower surface only, simple, unicellular, unbranched. Vein islets 6 W. tomentom R. & S. (average) per sq. mm. Vein endings 16 (average) Macro-characters : Leaves opposite, simple, short- per sq. mm. ly petiolate ; petiole upto 0.5 cm long, pubescent ; lamina almost ovate or elliptic to elliptic-oblong, P. rubra Linn. forma acominsta Sant. & Irani ex shortly caudate-acuminate, base rounded or slightly Shah cuneate, upto 15 cm x 6.5 cm (upto 23 cm on new Macro-characters : Leaves alternate, getting branches coming out from the main bole of the tree crowded towards the end of the branches, simple, near the base), entire, chartaceous, upper surface petiolate ; petioles stout, 2.5-8 cm long, pubes- bright green, pubescent, lower surface rather paler, cent; lamina oblong or obovate-oblong or oblan- densely pubescent, nervation conspicuous, main ceolate, shortly acuminate, base cuneate and lateral nerves 8-15 pairs, midrib, laterals and ter- slightly decurrent, upto 48 cm x 14 cm, entire, tiaries raised beneath. coriaceous, upper surface dark green, glabrous or Microcharacters : Epidermal cells penta- or hexa- with few scattered hairs here and there ; lower gonal, upper sinuous walled, lower slightly sinuate. surface paler, pubescent or puberulus on the stout Stomata frequent on lower surface and rare on midrib and the lateral nerves and the margin. upper, lower zo x r 6.7 p (average), upper 25.5 x 18p nervation conspicuous, lateral nerves 25 to 30 pairs, (average), rubiaceous; stomatal index 22-23-24 (lower almost parallel, ultimately uniting into an intra- surface). Trichomes simple, unicellular, unbranched. 288 BULLETIN OF THE BOTANICAL SURVEY OF INDIA [Vol. I I

Vein islets 10 (average) per sq. mm. Vein endings 20 in W. tomentosa they are distinctly sinuous walled (average) per sq. mm. (Figs. 3 & 8). The cell walls of lower epidermis are DISCUSSION straight or almost straight in Plumeria alba, P. The epidermal characters and venation pattern rubra forma acuminata and il'rightia tinctoria ; provide valuable data to be taken use of in phylo- slightly sinuate in Alstonia uzcccrophylla and genetic and taxonomic considerations. These fea- Wrightia tomentosa; and distinctly sinuate in tures can profitably be used in standardising market Holarrhena antidysenterica. drugs. The stomata are absent (Fig. I) or very rare The important data regarding the cuticular struc- 2 & 3) in the upper epidermis, while frequent in tures and venation are presented in the Table. The the lower one. They are generally rubiaceous type investigations reveal that in the species studied here, epidermal cells are generally penta- or hexa-gonal. They are straight walled in upper surface in Als- tonia rnacro$hylla (Fig. q), Holuvrhena antidysen- terica (Fig. lo), Plumeria alba (Fig. I) and P. rubrn forma aczclninata (Fig. 6) while in Wriglitia tinc- toria (Figs. 2 & 7) the cells are slightly sinuate and

Figs. 15-20. Venation Pattern of : 15. A. macrofihylla. 16. Holar- ,hem antidysenterica. 17. Plumeria alba. 18. P. rubra forma acuminafa. 19. Wrightia tinctoria. 20. W. tomentosa.

but in Holarrhena antidysenterica and AEstonia macrophylla ranunculaceous type are also observed, interspersed with the normal tvpe. The stomata Figs. 1-1 1. Foliar epidermis of : 1. Plumeria alba. 2. Wrightia of upper epidermis, when pres;nt, are usually, of tinctoria & 3. W. tomentosa (all upper). 4. Alslonia macrophylla. 5. Plumeria alba. 6. P. rubra forma acuminata. 7. WrightM larger size than that of the lower surface. In some tincfmia & 8. W. tomentosa (all lower). 9 & 10. Holanhena antidy- species, viz., Alstonia macrophylka (lower surface) smtnica (showing striations on lower and upper surface respectively). 1 1. Plumeria rubra forma acuminata (showing stria- and Wrightia tinctoria, there is a considerable tions and giant stomata on lower surface). Figs. 12-14. range of variation in the size of the stomata. Frichomes : 12. From lower surface of P. rubra forma acuminatu. 19. From upper surface of Wrightia tomenfosa. 14. From lower In case of Plzcmeria rubra forma acuminata giant surface of Alstonia macrophyI1a. stomata were observed on the lower surface, in 19691 CHANDRA et al.: EPIDERMAL AND VENATION STUDIES IN APOCYNACEAE-I 289 addition to the normal ones (Fig. I I). It is noticed The trichomes are mostly present on the veins. that generally a good deal of variation occurs in In Wrightia tinctoria there are no trichomes; in stomata1 index of the same species, but in Wrighi- Plumeria alba the trichomes are completely absent ia tomentosa the variation is very little. on the upper surface. Trichomes, in all the species

TABLE

Cuticukrr structures 0) Vmatwn pattern of some Apocynacew

Stomata Epidermal Cell wall Venation Kame of species Tw* Stomata1 Index Average size (p) Lower Upper Vein Vein islets per ending sq. mrn per sq. mm -- Lower Upper Lower upper 1. Alsth macrophylla Ru with 15-18-22 - 20 x 13.7 - Vightly Straight 26 21 Ra rarely sinuous 2. HoImrhat~ Ru with 10-12-16 - 21 x15 - Sinuous Straight 8 19 antidy~nte&~ Ra rarely

3. PlumcrM alea Ru 16-20-24 - 38~16.7 - Almost Straight- 6 16 straight 4. Ph~~riarubra forma acuminata Ru 11 -14-21 3-44 25.3 X 19 33 ~22 Straight Straight 11 19 5. Wriphtio t&tmja Ru 18-21 -24 Rare 23.3 x 18.7 29 x25.7 Straight Slightly 20 33 ainuoua 6. WWia tomsntosa Ru 22-23 -24 Rare 20 x 16.7 25.5 x 18 Slightly Sinuous 10 20 sinuous

studied, are simple, unicellular and unbranched species, they are either radiating from or parallel (Figs. 12-14). to stomata or form irregular pattern. The data regarding the vein islets and vein ACKNOWLEDGEMENTS endings are given in the Table and also illustrated Thanks are due to Director, National Botanic (Figs. 15-20) to facilitate the identification. In case Gardens, Lucknow for providing facilities, Shri S. N. of Wrightia tinctoria (Fig. 19) and Holarrhena Vishkakarma for illustrations and Shri R. S. Ojha antidysmterica (Fig. 16) the vein islets are corn- for help in collecting material. pratively much smaller in size and thus are larger REFERENCES in number. The number of vein endings per sq. FLORIN,R. Untenuchungen zur stammesgeshichte dm Conifmalea unit area is very high in case of WTightia tinctolk und Cordaitales. Kgl. SvmrkaVctmskapsokad. Handl. Stockholm (Fig. 19)-Also the vein endings in Wrightia tinctoria Ser. 3, Band 10.1931. FOS~R,A. S. AND E. M. GIPPORD.Comparative morpholo of have slightly swollen apices. In case of Holarrhenfi ~scular)lanh.W. Ii. Freeman & Co., San Francisco, 189. antidysenterica the veinlets are mostly continuous HARRIS,T. M, On the taxonomic value of the anatomical structure of the vegetative or ans of dicotyledom 1V. F&l with the result that the vein endings are less fre- plants. &. &n. 4c. Lon! 155 : 221-222, 1942-43. quent. Sow, R. R. AND P. H. A. SNEATH. ~plesqfflumricd cuticular striations arc mostly presmt in all the Taxonomy. W. H. Freeman & GO., London, 1963.