Proc. lndian Acad. Sei. (Plant Sci.),Vol. 92, Number 5, October 1983,pp. 421-441 9 Printedin India.
Structure, distribuflon and classitication of plant trtchomes in relation to taxonomy III. Papilionoideae
P LEELAVATHI and N RAMAYYA Plant Anatomy and Taxonomy Laboratory, Dr of Botany, Osmania University, Hyderabad 500 007, India
MS received 13 Apri11982; revised 1 June 1983
Abstm~ A detailed structure, organographie distribution, classification and taxonomic significaneeof trichomes in 42 species in the subfamilyPapilionoideae is presented. In aU, 28 t¡ types are recognised in the taxon, of which 9 ate newly described. The trichome types fit into four categories in accordance with the classificationby Ram ayya (1975). Based on the dist¡ of trichome eategories, the Papilionoideae sectas more related to the subfamily Mimosoideae than to the Caesalpinioideae. A key is provided'for the identifiea- tion of the species, based on the foliar trichomes.
Keywo~h. Papilionoideae;trichomes; structure; distribution; elassification; taxonomy.
1~ Introduction
The trichomes in Papiiionoideae were investigated asa part of anatomical studies (Debold 1892; Solereder 1908; Sabnis 1920); Metcalfe and Chalk 1950; Korsmo 1954; Lackey 1978), or they were specificaUy studied ~Baudet 1973; Shah and Kothari 1973, 1975; Kothari and Shah 1974; 1975; Chakraborthy 1975; Kannabiran 1975; Baudet and Marecha11976; Flores and Epinoza 1977; Gupta and Murthy 1977; Lackey 1981). However, information about their structure, organographic distri- bution, classification and taxonomic significante is rather scant; hence they have been made the subject-matter of investigation in the subfamily to supplement data for the family Leguminosae (Leelavathi and Ramayya 1982, 1983). The vegetative and floral organs are studied (table 1).
2. Material and methods
Of the 42 species studied (ta,ble 1) 39 were locally collected, while Erythrina blakei Hort. ex. Parker, Pterocarpus marsupium Roxb., Sophora glauca Lesch, and Zornia gibbosa Span. were obtained from outside Hyderabad. Young and rnature parts of the collected materials were fixed in Carynoy's fixative (Johansen 1940). To get an integrated picture of the trichome types and their organographic distribution, varied micropreparations viz.; epidermal peels, mounts of cleared whole organs or their portions, scrapings of trichomes and microtome sections were used. Epidermal peels were removed from all mature plant parts---leaflet,petiolule, stipel, petiole, stipule, stem, peduncle, pedicel, bract, bracteol, sepal, petal, androecium and gynoe- cium by scraping with a scalpel, wherever possible. In case of diŸ materials, peels were separated by following the "double-treatment rnethod" 421 Table 1. List of species investigated along with organographic distribution of vegetative trichomes. p,. I%
o E E
SI.No. Name of the species and Dichome types a b c d e { g h i j k 1 m n o p
( 1 ) A brus precatorius L. 1. Unicell. conical -- * * ...... LM w m 2. Uniser. fili. clavate -- * * + - + + .... m 3. Uniser. macro, conical B * * + LM + + + LM LM BM w -- +
12) Aeschynomene indica L.
1. Multiser. napiform M * * 4- M + * 4- M M M M - - - +
(3). Alysicarpus hamosus Edgew. 1. Uniser. fili, eapitatr L * * ...... * - + 2. Uniser. fili. clavate L * * + BM + + - M * LM + 3. Uniser. fili. eylindrie-clavate - * * - - - + - - * LM
m 4, Uniser, fili, obpyriform - * * - - - + + - * B - 4-
5, Uniser. fili. uncinate BM * * + M + + + BM * M - 4-
6. Uniser. macro, conical BM * * + M + - - M * LM - 4-
7. Uniser. macro, uncinate BM * * - - + - - * - - 4-
(4). Alysicarpus monilifer (L.) DC. 1. Uniser. fili. capitatr B * * ...... 2, Uniser. fili. clavatr M * * + LM + § - M - BM - 4-
J 3, Unisr fili, obpyriform L * * - - - + + L - BM - 4-
w 4. Uniser. fili. uncinate Bl~l * * + M + 4- + BM LM BM - 4- SINo. Name of the species and Dichome types a b c d r { g h i j k I m n o p
S. Uniser. macro, conical LM " * + M + + - UM - LM .... + 6. Uniser. macro, uncinate L * * - - - + + ...... + (5). Alysicarpus rugosus (Willd.) DC. "S 1. Uniser. fili. capitate
2. Uniser. fili. clavate M * * - BM - + - L , B .... + 3. Uniser. fili. obpyriform BM | * - - - - + LM * BM .... + 4. Uniser. fili. uncinate L * * + BM + - - LM * BM .... + 5. Uniser. macro, conical M * * - M - + - M * LM .... + 6. Unisr macro, uncinate + + LM * BM .... + (6). Arachis hypogaea L. 1~ Uniser. fili. conical BM + * + LM + + LM LM LM ..... 8" 2. Uniser. macro, conical BM + * + M + + LM LM LM ..... 3. Multiser. conical
4. Multiser. vcntricose - L L L ..... (7). Atylosia scarabaeoides (L). Benth.
1. Uniser. fili. capitate B * * + -- + + + LM * BM .... + 2. Uniser. fili. obpyriform B * * - L - 3. Uniser. fili. vesicular clavate BM * * + L + + + Lh * s .... + 4. Uniser. macro, conical BM * * + LM + + + LM * BM .... + (8). Butea monosperma (Lam.) Taub. 1. Uniser. fili. clavate L * * + LM + + + LM * BM .... + 2. Uniser. macro, conical BM * * + LM + + + LM * BM .... + c) {9). Cajanus cajan (L.) Millsp. 1. Uniser. fili. clavate B * * + LM + + + M * BM .... + 2. Uniser. fili. obpyriform BM * * - M - - + UM * M .... + 3. Uniser. fili. vesicular clavate B * * + LM + + + LM * BM .... + 4. Uniser. macro, conical BM * * + LM + + + BM * BM .... + (10). Canavalia ensiformis (L.) DC. 1. Uniceli. conical - - M M BM .... q- 2. Uniser. fili. clavate BM - BM + BM + 4 = 4- - - BM L - - - 4- 4~ 3. Uniser. fili. cylindric-clavate (,~ continued 4~ SINo, Name of the species and Dichome types a b c d e f g h i j k I m n o p to
4. Uniser. fili. uncinate -- + LM - BM - + + M M LM ..... 5. Uniser. macro, prickle BM + LM + LM + + + LM LM BM L .... (!1). Cicer arietinum L. 1. Unicell, Cylindrical 2. Uniser. fili. ovalis-ca~itate BM * * + BM + * + BM * BM L - - - + g" 3. Uniser. fili, cylindrical h" 4. Uniser. fil[. cylindric.clavate - * * - - * - - * - - M - - - 5. Uniser. macro, conical BM * * + BM + * + BM * BM .... + (12). Clitoria ternatea L. ~~ 1. Uniser. fili. capitatr BM + BM + M + * + LM LM ...... r191 2. Uniser. fili. clavatr BM + M + BM + * + BM LM LM BM - - - + 3. Uniser. fili. uncinate BM + BM + BM + * + BM BM BM BM M M - + 4. Uniser. macro, conical BM + LM + LM + * + LM LM LM M - - + + (13). Crotalaria biflora L. 1. Unisr macro, conical BM * * + BM + * + LM * LM L .... (14). Crotalaria lab~urnifolia L. 1. Uniser. macro, conical LM * * + * + + + LM LM ...... (15). Crotalaria pusilla L. 1. Uniser, macro, conical BM * * , * + * + LM ~' LM .... * (16). Crotalaria ramosizsima Roxb. * , * + * + 1. Uniser. macro, conical BM * L * ..... + (17). Crotalaria verrucosa L. 1. Uniser. macro, conical BM * * + BM + + + LM LM BM U - M - + (18). Dalbergia sissoo Roxb. 1. Uniser. macro, conical BM + * + BM + + + LM LM LM .... + 2. Multiser, ovate O -- U ~ -- -- M M ...... (19). Derris scandens (Roxb.) Benth. 1. Uniser. fili. elavate L + * + BM + + + LM LM ...... 2. Urdser. macro, conical BM + * + LM + + + LM LM LM M M M - + 3. Uiser. macro, cylindric-clavate -- i , _ _ _ + + SINo. Name of (he species and Dichome types a b c d r f g h i j k ! m n o p
(20). Desmodium triflorum (L.)DC. 1. Uniscr. fili. capitatr L * * - - - * - - * L - - 2. Uniser. fi[i. clavatc M * ~ + BM + * + LM * LM - - 3. Uniser. fili. cylindric.clavatr M * * - M - * - LM * - - - 4. Uniscr. fili. obpyriform 5. Uniscr. fili. uncinatr L * * + B + * + LM * LM - - o 6. Uniscr. macro, conical LM * * + M + * + LM * LM - - 7. Uniser. macro, uncinat• (21). Dolichus lablab L. I. Uniscr. fili. ciar,te B + B + L + + + L L BM - 2. Uniser. macro, conical BM + BM + LM + + - LM LM BM - 3. Uniscr. macro, prickle - + - + - + .... L 8" o (22). Erythrina blakei Hort. Ex. Parkcr t. Uniser. fili. clavatr BM t t t t t t t t t t t t t t t 2. Unisr macro, str162 BM, t t t t t t t t t t t t t t t (23). Erythrina orientalis (L.) Murr. 1. Uniser. fili. ciar,te BM + BM + BM + § + LM LM BM - - 2. Uniser. macro, stellatr BM + U + BM + + + LM LM LM - - (24). Erythrina suberosa Roxb. i. Uniser. fili. clavate BM + BM + BM + + + LM LM BM .... + 2. Uniscr. macro, stcllatr BM + B + BM + + + LM LM LM .... + (25). tteylandia latebrosa DC. Uniscr. macro, conical BM * * * * + * + LM * LM .... + o (26). Medicago sativa L. 1. Uniser. fili. ciar,te LM + # + LM + + + - * BM - - _ _ + 2. Unisr fili. r237 - - * ...... " BM - - 3. Unis•r. fili. cylindric.clavatr - - ) ...... ) BM - - 4. Uniscr. inacro, conical L + * + LM + + + - * BM - - (27). Meliiotus alba Dcsr. 1. Uniser. fili. clavatr LM + * + BM + + + LM * LM .....
2. Uniser. fili. cylindric-clavatr - - ~ ...... * BM ..... (3n continued SINo. Namr of the species and Dichome Ÿ a b c d r ( g h i j k I m n o p "~'
3. Uniser. macro, conical BM + + BM + + + LM, * BM ..... (28). Melilotus indica AII. 1. Uniser. fili. clavate LM + * + BM + + + M * M ..... 2. Uniser. macro, conieal LM + * + LM + + + LM * BM ..... (29). Mucunapruriens (L). DC. 1. Unisr fili. clavatr - - ~ + M + + + LM LM LM - - - - + 2. Unisr fili. cylindric 3. Uniser. fili. vesicular clavate LM + - + LM + + - - * BM L - - - + 4. Uniser. macro, conieal BM + LM + LM + + + LM * BM B - - - + (37). Sophoraglauca Lesch. !. Uniser. macro, conieal BM t t t t t t t t t t t t t t t (38). Stylosanthes fruticosa (Retz.) AIston 1. Uniser. fili. flagellate BM * * + LM + * - BM BM M' - .... o 2. Uniser. macro, conical _ + LM + * - M M ..... + 3. Multiser. conical - * ~ - - - * - U ...... 4. Multiser. ventricose LM * * + LM + * ...... (39). Trigonellafoenum-graecum L. 1. Uniser. fili. clavate _ + M + - - BM * BM ..... 2. Uniser. macro, conical LM * * + BM + + + BM * BM ..... o (40). Vignacylindrica (L). Skcels. 1. Uniser. fili. clavate BM + L + LM + * + LM * BM .... + 2. Uniser. fili. cylindrier ...... * - M * M ..... 3. Uniser. macro, conical UM + - + M + * + LM * M .... + 4. Uniser. macro, prickle BM ..... * - M * BM .... + (41). Zornia diphylla (L.) Pers. 1. Uniser. macro, conieal LM * + - + * - M M LM ..... 2. Multiser. fusiform - * * + LI - * - U U ...... (42). Zornia gibbosa Span. 1. Unicell. conical _ _ _ _ _ , ...... + o 2. Llniser. macro, conical LM + * + - + * - M M LM ..... o 3. Multiser. fusiform - - * + U - * - U U ...... + = Trichome type present; - = Trichome type absent; * = Organ absent; t = Organ not studied; B =Trichome type present on adaxial and abaxial surfaces; BM = Trichome type present on adaxial, abaxial suffaces and margins; L = Trichome type present on abaxial sur- face; LM = Trichome type present on abaxial sufface and margins; M = Trichome type present on margins; U = Trichome type present on adaxial surface; UM = Trichome type present on adaxial surface and margins; fili. = Filiform" macro. = Macroform; Multiser. = Multi- seriate; Unieell. = Unicellular; Uniser. = Uniseriate; a = Leaf (let); b = Petiole; c = Stipel; d = Primary rachis/Petiole; e = Stipule; f = 4~ Stem; g = Peduncle; h = Pedicle; i = Bract;j = Bracteole; k = Sepal; I = Standard petat; m = Wing petal; n = Keel petal; o = Androecium:. bO p = Gyneocium. 428 P Leelavathi and N Ramayya (Leelavathi and Ramayya 1975). Mounts of isolated trichomes were essen- tial to study the morphology of individual trichomes. Trichomes were sepa- rated by scraping the plant organs with a scalpel or blade or directly crushing shoot apiees, after treating them with dilute aeids. In aU the locally collected ptants, a minimum of five samples from different localities were studied, to observe the range of variation regarding the size and frequency of trichomes. Permanent Cariada balsc, m mounts of microtome sections of vegetative and floral buds were made for all the species by following the usual paraffin embedded method (Johansen 1940). Stain combinations employed were Ehrlieh's hema- toxylin with basic fuchsin as counterstain. These preparations were particularly essential to make a thorough study of the distr~bution of trichomes. 3. Observatlons Presently 22 trichome types have been observed of which, some occur in only one species, while others occur in more than one species in varied combinations (table 1). In no one species all the types are found. Besides the qualitative and quantitative differences the trichomes exhibit, their dispersion is variable from one taxon to the other, from one organ to the other as well as from one surface to the other of a given organ (table 1). The general description of the trichome types is as follows: 3.1 Unicellular conical hair Unieellular, conical, longer than broad, pointed at apex; contents scanty; waU thin or slightly thick; surface smooth (figure 1). *3.2 Unicellular cylindrical ha& Similar to unicellular conical hair, but cylindrical, obtuse at apex (figure 2). *3.3 Uniseriate filiform conical hair Foot: 1-celled; eontents scanty; wall thin. Body: Unieellular to uniseriate, 1 to 4- celled in length, pointed at apex. Cells of varied lengths, basal cells mostly broader than long, terminal eeU quite longer than broad; eontents dense; early evanescent; walls thin; surface smooth (figures 30,31). 3.4 Unisariate filiform cylindrical hair Similar to uniS'eriate filiform conical hair except Body: Apex obtuse, cells of almost equal length (figures 17,18). *3.5 Uniseriate filiform flagellate hair Similar to uniseriate filiform conieal hair except Body: 2 to 4-celled in length, subterminal eell swollen in some. Terminal eell quite long, flagellate (figures 19,20). | recorded trichome types (not described in ~he past in Papilionoideae). Trichomes of Papilionoideae in relation to taxonomy 429 I 3,5,7, 8,zz,15 s,J3,191 J Figures 1-25. (See caption on page 441). 430 P Leelavathi and N Ramayya 3.6 Uniseriate filiform uncinate hair As in uniseriate filiform conical hair except Body: Unicellular, distally curved into a hook, quite longer than broad, lateral walls increasingly thickened towards the distal end (figure 16). 3.7 Uniseriate filiform cylindric-clavate hair Similar to uniseriate filiform cylindrical hair except Body: 4 to 8-celled in length, c~r contents dense throughout or in few terminal cells (figure 13). 3.8 Uniseriate filiform obpyriform hair Foot: 1-celled; contents scanty; wall thin. Stalk: Unicellular, broader than long or absent. Body/Head: Uniseriate to multiseriate, obpyriform with a long neck; basal part swollen, 7 to 13-celled in length; 1 to 5-celled in width in the basal region, while 1 to 3-celled in terminal part. Cells usually slightly broader than long in basal ones, quite longer than broad above; terminal cell distinct or indistinct, ir distinct capitate or clavate or conical with contents dense near basal part, scanty above, or scanty or dense throughout, surface smooth (figures 9-12 and 14). 3.9 Uniseriate fili]orm capitate hair Foot: 1-celled; contents scanty; wall thin. Stalk: Unicellular to uniseriate, cylindrical, 1 to 5-celled in length. Cells of varied lengths, longer than broad or broader than long; contents scanty; walls thin. Body/Head: Unicellular to multiseriate, capitate, 1 to 6-celled in length, 1 to 4-celled in width, often in tiers; cells of varied lengths, mostly broader than long, few longe'r than broad; contents dense; walls thin; surface smooth (figures 3-5 and 8). 3.10 Uniseriate filiform clavate hair Similar to the uniseriate filiform cylindrical hair except Stalk: 1 or 2-celled in length and width; Head: Clavate, 2 to 5-celled in length, 2 to 4-celled width; contents dense (figures 6,7). 3.11 Uniseriate filiform vesicular clavate hair Similar to the uniseriate filiform clavate hair except Stalk: Absent. Body: 4 or 5- celled in length, 1 or 2-celled in width. Cuticular vesicle formed all over the body: vesicle spherical to orate, at maturity with yellowish contents (figure 15). 3.12 Uniseriate filiform o valis-capitate hair Similar to the uniseriate filiform capitate hair except Stalk: 2 to 4-celled cells quite long. Head: Oval, 4 or 5-celled in length, 1 to 3-celled in width (figures 21-23). 3.13 Uniseriate macroform conical hair Foot: 1 or 2-celled; contents scanty; walls mostly thick (in some subtended by an emergence) Body: Unicellular or uniseriate, 1 to £ in lengt¡ conicaL pointed at apex, terminal cell quite long, basal cells broader than long, rarely length oŸ Trichomes of Papilionoideae in relation to taxonomy 431 terminal cell equal to that of the basal ones; walls quite thick; surface smooth or verrucose (figures 26-29, 32-36, 39 and 40). *3.14 Uniseriate macroform cylindric-clavate hair Similar to the uniseriate macroform conical hair except Body: Cylindric-clavate, 2- celled in length, basal cell broader than long, terminal cell quite longer than broad; surface smooth (figure 37). "3.15 Uniseriate macroform prickle hair Similar to the uniseriate macroform conical hair except Body: Unicellular, prickle- like; walls evenly thickened (figure 25). 3.16 Uniseriate macroform stellate hair Foot: 1-celled, contents scanty; wall thin. Stalk: Uniseriate, cylindrieal, 3 to 10- celled in length, cells of varied lengths, broader than long or vice versa; contents dense; walls thin; surface smooth. Head: Unicellular, stellate, 4 or 5-armed, some arras d(chotomously divided, each arm tapering towards the tip; contents scanty; waUs thick; surface smooth (figure 38). 3.17 Uniseriate macroform uncinate hair As in uniseriate filiform uncinate hair, but quite robust (figure 24). 3.18 Multiseriate conical hair Foot: Multicellular; cells juxtaposed; contents scanty; walls thin. Bodv: Multi- seriate, conical, gradually tapering above, 12 to 25-celled in length; 1 to 5-eeUed in widthi cells of varied lengths, longer than broad; contents scanty; walls slightly thick; surface smooth (figure 44)~ *3.19 Multiseriate ventricose ¡ Sim~lar to the multiseriate conical hair except Body: Ventricose, broad at base, tapering above; 13 to 30-celled in length, 1 to 13-celled in width. Cells slightty longer than broad or broader than long in the proximal hall; quite long in the distal half; contents scanty throughout or dense in the proximal part; walls thick; surface smooth (figures 42,43). *3.20 Multfseriate napiform hair Foot: Multicellular; cells juxtaposed; contents scanty; walls thin. Body: Multi- seriate, napiform, swollen at the base, abruptly tapering above, capitate at the apex 10 to 14-celled in length and 4 to 7-celled in width in the proximal swollen part: 5 or 6-celled in length and 1 or 2-celled in width in the distal tapering part. Celts mostly broader than long, few slightly longer than broad in the basal half, quite longer than broad in distal part; contents dense in the basal part, scanty in distal part: walls thin; surface smooth (figure 47). 432 P Leelavathi and N Rarnayya *3.21 Multiseriate fusiform hair Similar to the multiseriate conical hair except Body: Fusiform, 10 to 24- celled in length, 2 to 6-celled in width; contents dense (figure 46). *3.22 Multiseriate ovate hair Foot: Multicellular; cells juxtaposed; contents scanty; walls thin. Stalk: Multi- seriate, cylindrical, 3 to 5-eelled in length. 2 or 3-celled in width; cells mostly longer than broad, in some broader than long, contents scanty or dense; walls thick. Head: Multiseriate, ovate, 7 to 10-celled in length, 3 to 7-celled in width. Cells of varied lengths, mostly broader than long, few slightly tonger than broad; contents dense; walls thin; surface smooth (figures 41,45). 4. Discusston 4.1 General features Earlier in this subfamily only multieellular trichomes consisting of uniseriate to multiseriate structure were recorded (Solereder 1908; Sabnis 1920; Metcalfe and Chalk 1950; Shah and Kothari 1973, 1975; Kothari and Shah 1974, 1975; Kannabiran 1975; Lackey 1981). This is confirmed presently besides, observing two hair types of unicellular category viz., unicellular cylindriCal hair on the sepal of Cicerarietinum (figure 2) and unicellular conical hair, on various parts of Abrus precatorius, Canavalia ensiformis, Pterocarpus marsupium and Zornia gibbosa (figure 1, table 1). Variation in the structure of a foot is common in Leguminosae (Leelavathi and Ramayya 1982, 1983). The foot is 2-ceUed in Butea monosperma, otherwise 1-celled or indistinct in the multiseriate triehomes. The projecting foot cell in most of the uniseriate macroform conical hairs in the two subfamilies viz., Caesalpinioideae and Mimosoideae (Leelavathi and Ramayya 1982, 1983), is rather uncommon Ÿ the triehomes of Papilionoideae (figures 26-28). Length and width of the trichome types have been shown to be taxonomically significant (Ramayya. 1962; Prabhakar and Ramayya 1975; Leelavathi and Ramayya 1982, 1983), similar importante has also been noticed in Papilionoideae. The longest observed trichome is 3200 lam (figure 26), while the shortest is 20 lam (figure 3), the broadest is 250 lJm (figure 47) and the thinnest is 3 lam (figures 30, 31). Trichomes may be one-celled in height (figures 1, 2) or 2 to 25-celled (figures 3-47)~ In width the number of cells may vary from 1 to 10-cells (figures 1-47). Trichome cells are varied in size which is of taxonomic value, but to a limited extent. The longest (2900 lam) observed is the terminal cell (figure 26) and shortest (10 lam) is the basal cell (figure 31). Similarly, the broadest (175 lam) is represented by the terminal cell (figure 38) while the thinnest (3 lam) by the terminal cell (figure 31). Different trichome types possessing cuticular vesicle were reported ir~ varied families (Solereder 1908; Metcalfe and Chalk 1950; Ramayya 1962; Uphof 1962; Bhattacharya and Maheshwari 1973; Rajagopal 1973). The vesicle position is terminal (Ramayya 1962; Uphof 1962) or lateral (Uphof 1962; Rajagopal 1973) and Trichomes of Papilionoideae in relation to taxonomy 433 ?SO,um s0V,,, 91~33 1,2 38 H / . .500 pro .91 5O 37, 26 2~,2a-31,,~~,36 30O pro Figures 26..43. (See caption on page 441 ). 434 P Leelavathi and N Ramayya Flgures45-47. Trichomes of Papilionoideae 45. Arachis hypogae: Multiseriate conica[ hair from T S primary rachis 46. Dalbergia sissoo: Multiseriate orate hair from T S stipule 47. Zornia diphylla: Multiseriate fusiform hair fromT S primary rachis. according to Uphof (1962) few body cells of trichomes disorganise to forma yellow fluid whieh collects in the cuticular vesicle.Presently the terminal vesicle has been noted in the uniseriate filiform vesicular clavate trichome of Atylosia scarabaeoi- des, Rhynchosia aurea and R. mŸ (figure 15, table 1). However, in this trichome type. all the body cells disorganise to forro the yellow fluid. Kothari and Shah (1975) described glandular trichomes on the abaxial leal- lamina in Zornia diphylla. The present study however reveals them to be secretory eavities, rather than trichomes and they are of mesophyll origin, as also described by Solereder (1908). Lateral and eross walls of trichomes are slightly thick or thin as recorded in many taxa (Ramayya 1962; Prabhakar and Ramayya 1975; Leelavathi and Ramayya 1982, 1983). Wall surfaces in the triehomes presently studied are either smooth or verrucose. Trichomes of Papilionoideae in relation to taxonomy 435 4.2 Trichome types and their classification Several trichome types have been described earlier in Papilionoideae (Solereder 1908; Metcalfe and Chalk 1950; Korsmo 1954; Shah and Kothari 1973, 1975, Kothari and Shah 1974; Kannabiran 1975; Lackey 1978), but out of these only 19 types could be certainly discerned, since the remaining are without precise illustrations and/or descriptions. The names of the trichome types known from the past are often confusing (Leelavathi and Ramayya 1983), hence they have been renamed on a uniform basis, keeping their structural features under consideration. Consequently the 19 trichome types recognised from the past literature have been also given new names treating their previous names as synonyms viz., 1. Unicellular conical hair (Syn. Unicellular branched hair). 2. Unicellular ramose hair (Syn. Unicellular branched hair). 3. Uniseriate filiform cylindrical hair (Syn. Uniseriate glandular hair). 4. Uniseriate filiform uncinate hair (Syn. Uniseriate hooked hair). 5. Uniseriate filiform cylindric-clavate hair (Syn. Nectar gland). 6. Uniseriate filiform obpyriform hair (Syn. Bulbous glandular hair). 7. Uniseriate filiform eapitate hair (Syn. Glandular hair). 8. Uniseriate filiform ovalis-capitate hair (Syn. Glandular hair). 9. Uniseriate filiform vesicular capitate hair (syn. Spherical headed gland). 10. Uniseriate filiform clavate hair (Syn. Club-shaped gland; Nectar gland). 11. Uniseriate filiform vesicular clavate hair (Syn. Nectar gland). 12. Uniseriate macroform conical hair (syn. Simple uniseriate hair). 13. Uniseriate macroform uncinate hair (Syn. Uniseriate hooked hair) 14. Uniseriate macroform two-armed hair (Syn. Uniseriate two-armed hair). 15. Uniseriate macroform stellate hair (Syn. Branched trichome; Stellate hair). 16. Multiseriate multifluked anchor hair (Syn. Anchor like shaggy hair). 17. Multiseriate hollow-peltate hair (syn. Peltate gland). 18. Multiseriate peltate hair (Syn. Peltate gland). 19. Multiseriate conicaI hair (Syn. Conical shaggy hair). Of the 19 trichome types recorded earlier, 13 have been presently confirmed (not asterisked in the text) and nine more types have been newly observed (asterisked in the text). Thus a total of 28 trichome types ate recognised for the subfamily Papilionoideae based on the past and present information. Ramayya (1975) recognised in all, five major categories in the angiosperm trichomes viz., unicellular trichomes, uniseriate filiform trichomes, uniseriate macroform trichomes, biseriate trichomes and multiseriate trichomes. Since this classification is based on mature structure of the trichomes and is unambiguous unlike those of Weiss (1867), De Bary (1884), Solereder (1908), Metcalfe and Chalk (1950), Hummel and Staesche [ 1962) and Theobald et al (1979) which ate based on either structure-cum-function of merely forro or function of a combination of all the three characters viz. forro, function and structure (see also Leelavathi and Ramayya 1982), we have preferred to classify the trichomes of the Papilionoideae according to the classification given by Ra'mayya (1975). The trichomes of this sub- 436 P Leelavathi and N Ramayoya family rail under four of the five categories as given below: (i) UniceUular trichomes (trichomes 3.1, 3.2 in the text) (ii) Uniseriate filiform trichomes (trichomes 3.3-3.12 in the text) (iii) Uniseriate macroform trichomes (trichomes 3.13-3.17 in the text) (vi) Multiseriate trichomes (trichomes 3.18-3.22 in the text). 4.3 Taxonomic importance Uniseriate macroform conical hair with a long terminal cell is a characteristic feature of the Papilionoideae except in Ononis and Amicia zygomeris (Solereder 1908; Metcalfe and Chalk 1950). Presently it is confirmed except in Crotalaria verrucosa wherein the body cells of few trichomes are of equal length (figure 40). In Erythrina uniseriate macroform stellate hair and uniseriate macroform two- armed hair have been earlier reported (Solereder 1908; Metcalfe and Chalk 1950). In the 3 species of Erythrina presently investigated, while the former type is confirmed (figure 38), the latter was not observed (table 1). Uniseriate macroform uncinate hair and uniseriate filiform uncinate hair have been reported in several genera viz., Alysicarpus, Canavalia, Clitoria, Desmodium, Phaseolus (Solereder 1908; Metcalfe and Chalk 1950; Lackey 1978, 1981), they are now confirmed except in Phaseolus (table 1). Based on the morphology of stipules, keel petal, coloration of flower and other floral characters, seed and seedling leaf, shape of the pod, sexual compatibility and geographical distribution it has been suggested that Asian Phaseolus species can be shifted to the genus Vigna (cfAnon 1969). Lackey (1981) also treated those species of the Phcseolus which do not possess uniseriate filiform uncinate and uniseriate macroform uncinate hairs to belong to the genus Vigna. The present study supports the treatment of Lackey (1981). Earlier multiseriate trichomes have been noted in Arachis, Aesychenomene and Stylosant¡ (Solereder 1908; Metcalfe and Chalk 1950). Ir is now confirmed and also ascertained in three more species belonging to two genera viz., Dalbergia sissoo, Zornia diphylla and Z. gibbosa (figures 41,45 and 46, table 1). Pongamia is a monotypic genus showing perplexing forms ranging in habit from trees to climbers, and from white to violet flowers (Baker 1879; Anon 1969). Based on chemical investigations Khanna and Seshadri (1964) have considered the Australian Pongami` to be distinct from Asiatic ones. Solereder (1908) has recorded uniseriate filiform cylindrical hair in Pongamia. Since in the material presently studied which is a tree with violet flowers, the above trichome type is absent, it is suggested that the monotypic Pongamia species may representa complex taxon. Hence, it is desirable to make a cornprehensive study of the epidermis of this species occurring in varied geographical regions for understand- ing its true taxonomic status. "Erythrina alkaloids are reported from the genus Erythrina in the Leguminosae and from a few species in several unrelated families. The unusual structural features which these alkaloids exhibit as well as their restricted distribution within Leguminosae make them useful systematically" (Mears and Mabry 1971 ). It is quite interesting that the uniseriate macroform stellate hair is found only in this genus (table 1) singling it out from the rest of Papilionoideae (cf Leelavathi 1976; Lackey 1978) supporting the evidente from alkaloid distribution. Trichomes of Papilionoideae in relation to taxonomy 437 Tribes Hedysareae and Phaseolae (Sen. Str. Benthem and Hooker 1865) are unique in possessing epidermal crystals (Solereder 1908; Leelavathi 1976). This is also supported by the present observation of the uniseriate filiform uncinate and uniseriate filiform obpyriform hair types restricted to only these tribes. Relationship of the Papilionoideae with other subfamilies of Leguminosae is controversial (Corner 195i; Dnyansagar I955; Heywood 1971). Presently Papilio- noideae is suggested to be closer to the Mimosoideae, because the uniseriate filiform category of trichomes are so lar recorded only in these two subfamilies, and not in the Caesalpinioideae (Leelavathi and Ramayya 1982, 1983). From the table it is evident that some of the trichome types are restricted to a particular taxa viz., uniceltular cylindrical hair (CŸ arietinum), uniseriate filiform conical hair (Arachis hypogaeaL uniseriate filiform flagellate hair (Stylo- santhesfruticosa), uniseriate macroform cylindric-clavate hair (Derris.scandens), multiseriate napiform hair (Aeschynomene indica), multiseriate ovate hair (Dal- bergia sissoo). Hence these taxa can be directly identified from the others. Uniseriate macroform conical hair though widespread, having been noted in 37 species, is also taxonomically valuable in the Papilionoideae studied, since its foliar distribution varies from species to species (table 1). Thus based on the foliar trichome types, their distribution and size differences, the species presently studied, are all distinguishable, as keyed below: 5. Key |or the identification of the Papllionoideae spec|es la. Uniseriate macroform conical hairs absent. 2a. Uniseriate filiform flagellate hairs present...Stylosanthes fruticosa. 2b. Uniseriate filiform flagellate hairs absent. 3a. Uniseriate macroform prickle hairs present...Canavalia ensiformis. 3b. Uniseriate macroform prickte hairs absent. 4a. Uniseriate macroform stellate hairs absent...Aeschynomene indica. 4b. Uniseriate macroform stellate hairs present. 5a. Uniseriate filiform clavate hairs confined to midvein and lateral veins on adaxial surface only. 6a. Trichomes quite frequent...Erythrina suberosa. 6b. Trichomes rare...Erythrina blakeL 5b. Uniseriate filiform clavate hairs present all over on both surfaces .o. Erythrina orientalis. I b. Uniseriate macroforrn conical hairs present. Ta. Only uniseriate macroform conical hairs present. 8a. Trichomes absent on adaxial and present on abaxial surface and/or margins. 9a. Trichomes persistent on margins. 10a. Trichomes persistent on abaxial surface and margins. I la. Trichomes persistent on abaxial midvein only...Zornia diphylla. 1 lb. Trichomes persistent alI over on abaxial surface ... Trigonellafoenum- graecum. 10b. Trichomes persistent only on margins ... Zornia gibbosa. 9b. Trichomes not persistent on margins ... Crotalaria laburni/blia. 8b. Trichomes present on both adaxial and abaxial surfaces. 438 P Leelavathi and N Ramayya 12a. Trichomes present on margins. 13a. Trichomes mostly subtended by an emergence ... Heylandia latebrosa. 13b. Trichomes not subtended by an emergence. 14a. Body of the trichomes 2 to 4-celled long. 15a. Surface of the trichomes verrucose .,, Sophora glauca. 15b. Surface of the trichomes smooth. 16a. Trichomes sparse on adaxial; body of the triehomes 3 or 4-celled long ... Dalbergia xissoo. 16b. Trichomes quite frequent; body of the trichomes 2 or 3-celled long ... Pterocarpus santalinus. 14b, Body of the trichomes one-celled long. 17a. Trichomes dense on adaxial and abaxial surfaces. 18a. Trichomes up to 1000 pm long ... Crotalaria ramosissima. 18b. Trichomes up to 500 lam long ... Crotalaria pusilla. 17b. Trichomes dense on abaxial but sparse on adaxial surface. 19a. Trichomes 1000 to 1200/120 to 150 pm in length/width ... Crotalaria biflora. 19b. Trichomes 500 to 600/60 to 75 lato in length/width ... Crotalaria verrucosa. 12b. Triehomes absent on margins. 20a. Trichomes confined to ~eins on both surfaces ... Mucuna pruriens. 20b. Trichomes present all over on both surfaces .,. Abrus precatorius. 7b. Uniseriate macroform conical hairs along with other types of trichomes. 2la. Unicellular conical hairs present .~ Pterocarpus marsupium. 21b. Unicellular conical hairs absent. 22a. Uniseriate filiform conical hairs present ,. Arachis hypogaea. 22b. Uniseriate filiform conical hairs absent. 23a. Uniseriate filiform ovalis-capitate hairs present ... Cicer arietinum. 23b. Uniseriate filiform ovalis-capitate hairs absent. 24a. Uniseriate macroform prickle hairs present ... Vigna cylindrica. 24b. Uniseriate macroform prickle hairs absent. 25,a. Uniseriate filiform capitate hairs present. 26a. Uniseriate macroform uncinate hairs presnet. 27a. Uniseriate filiform obpyriform hairs present ... Alysicarpus monilifer. 27b. UniserŸ filiform obpyriform hairs absent ... Alysicarpus hamosus 26b~ Uniseriate macroform uncinate hairs absent. 28a. Uniseriate filiform uncinate hairs present. 29a. Uniseriate filiform obpyriform hairs present ... Alysicarpus rugosus. 29b. Uniseriate filiform obpyriform hairs absent. 30a. Uniseriate filiform cylindric-clavate hairs present ... Desmodium triflorum, 30b. Uniseriate filiform cylindric-clavate hairs absent ... Clitoria ternatea. 28b. Uniseriate filiform uncinate hairs absent. Trichomes of PaDilionoideae in relation to taxonomy 439 3la. Uniseriate filiform obpyriform hairs present ... Atylosia scara- baeoides. 31b. Uniseriate filiform obpyriform hairs absent. 32a. Uniseriate filiform vesicular clavate hairs absent on adaxial surface ... Rhynchosia minima 32b. Uniseriate filiform vesicular clavate hairs present on adaxial surface ... Rhynchosia aurea. 25b. Uniseriate filiform capitate hairs absent. 33a. Uniseriate filiform obpyriform hairs present ... Cajanus cajan. 33b. Uniseriate filiform obpyriform hairs absent. 34a. Uniseriate macroform conical hairs subtended by an emergente ... Phaseolus aconitifolius. 34b. Uniseriate macroform conical hairs without an emergence. 35a. Uniseriate filiform clavate hairs present on abaxial surface. 36a. Uniseriate filiform clavate hairs absent on margins. 37a. Uniseriate filiform clavate hairs confined only to the midvein and caducous ... Derris scandens. 37b. Uniseriate filiform clavate hairs present on all veins ... Butea mono- sperma. 36b. Uniseriate filiform clavate hairs present on margins. 38a. Uniseriate macroform conical hairs absent on margins ... Melilotus alba 38b. Uniseriate macroform conical hairs present on margins. 39a. Uniseriate macroform conical hairs present on adaxial surface ... Medicago sativa. 39b. Uniseriate macroforrn conical hairs present on both adaxial and abaxial surfaces ... Melilotus indica. 35b. Uniseriate filiform clavate hairs present on both adaxial and abaxial surfaces. 40a. Uniseriate filiform clavate hairs absent on margins ... Dolichus lablab. 40b. Uniseriate filiform clavate hairs present on margins. 4la. Uniseriate filiform clavate hairs confined to veins ... Pongamia pinnata. 4Ib. Uniseriate filiform clavate hairs present all over on both the surfaces ... Phaseolus trilobus. Acknowledgements The authors thank Prof. K V N Rao for facilities and encouragement. One of the authors (PI.) is also thankful to the Director, CCRH, New Delhi. References Anon 1969 The Wealth of India. A dictionary of Indian raw materials and industrial products VIII Ph-Re (New Delhi: CSIR) Baker J G 1879 Leguminosae; in Theflora of British India; (ed) J D Hooker (London: L. Reeve Co.) Baudet J C 1973 lnterest taxonomique des Carateres epidermiques dans le complexe Phaseolus-vigna; Bull. Soc. Bot. Belg. 106 53-59 Baudet J A and Marechal R 1976 Signification taxonomique de la presence do piols uncinul's chez certains genres de Phaseoleae et d' Hedysareae (Papilionaceae); Bull. Jard. Bot. Nat. Belg. 46 419-426 Bentham G and Hooker J D 1865 Genera Planatarum Vol.I (London: L Reeve Co.) 440 P Leelavathi and N Ramayya Bhattacharya B and Maheshwari J K 1973 Studies on extrafloral nectaries of the Leguminales 1. Papilionaceae with a discussion on the systematics of the Leguminales; Proc, lndian Acad. ScL 37 11-30 Chakraborthy N K 1975 Epidermal structure and stomataI characteristies of some Vigna species;J. BioL Sci. 18 64-71 Corner E J H 1951 The leguminous seed; Phytomorphology I 117-150 De Bary A 1884 Comparative anatomy of the vegetative organs of the pharnarogarns and lema. (Oxford: Clarendon Press) pp.54-66 Debold R 1892 Beitrage zur anatomis chan charkteristik der phaseoleen (Dissertation) (Reiff offen burg: Ludwrg-Maximiltian-Universitat; Munieh) Dnyansagar V R 1955 Embryological studies on the Leguminosae XII. Status of Leguminosae; Saugar Unir. J. 6 39-55 Flores E M and Epinoza A M 1977 The leal epidermis of Glycine soja Siet. et zuee; Rey. BioL Trop. 25 263-274 Gupta M and Murthy Y S 1977 Triehomes of Trifolieae; Proc. lndian Acad. ScL 85 77-89 Heywood V H 1971 The Le.guminosae -- A systematie purview; in Chemotaxonomy of the Leguminosae (eds) J B Harborne, D Boulter and B L Turner (New York: Aeademie Press) Hummel K and Staesche K 1962 Die Verbreitung derg Haartypen in den naturlichen Verwandtsehafts- gruppen in Encyclopedia ofplant anatomy (ed.) K Linsbauer (Berlin: Gertbrudex Borntraeger) Johansen D A 1940 Plant microtechnique (New York: MeGraw-Hill) Kannabiran B 1975 Epidermal structure and stomatal ontogeny of Zornia Gmel., Aust. J. Biol. 23 327-334 Khanna R N and Seshadri T R 1964 Chemical components of Pongamia pinnata: Seeds, flowers and stem bark: Curr. ScL 33 644-645 Korsmo E 1954Anatomy of Weeds (Oslo: Momliv) Kothari M J and Shah G L 1974 Observation on the structure of stomata and hairs in tribe Dalbergieae (Family Papilionaceae); Geobios 1 10-14 Kothari M J and Shah G L 1975 Epidermal str-~ture and ontogeny of stomata in the Papilionaeeae (Tribe Hedysareae); Bot. Gaz. 372-379 Laekey J A 1978 Leaflet anatomy of Phaseoleae (Leguminosae: Papilionoideae) and its relation to taxonomy; Bot. Gaz, 139 436-446 Laekey J A 1981 Distribution of hooked hairs in the Phaseolus-Vigna eomplex (Papilionoideae, Legu- minosae); Iselya 2 24-32 Leelavathi A 1976Epidermalstudies in the Leguminosae Ph.D thesis, Osmania University, Hyderabad Leelavathi A and Ramayya N 1975 Rapid isolation of leaf epidermis by double-treatment method; Geobios 2 117-119 Leelavathi P and Ramayya N 1982 Structure, distribution and classifieation of plant triehomes in relation to taxonomy I. Mimosoideae; Geophytology 12 3-21 Leelavathi P and Ramayya N 1983 Structure, distribution and classifieation of plant triehomes in relation to taxonomy II. Caesalpinioideae; lndian J. Forest 6 43-56 Mears J A and Mabry T T 1971 Alkaloids in the Leguminosae; in Chemotaxonorny ofLeguminosae (eds) J B Harborne, D Boulter and B L Turner (New York: Academic Press) Metealfe C R and Chatk L 1950Anatomy of the dicotyledons Vol.1 (London: Oxford University Press) Prabhakar M and l~amayya N 1975 Structure and development of trichomes in the family Portulaca- eeae; in Forra, structure andfunr inplants (eds) J J Shah and C K Shah, B M Johri Commemo- ration Vol. (Meerut: Sarita Prakashan Nanchandi) Rajagopal T 1973 Flora of Hyderabad including a study of the foliar epidermal charar of the species as an aid to taxonomy, Ph.D. thesis, Osmania University, Hyderabad Ramayya N 1962 Studies on the trichomes of some compositae 1 General structure: Bull. Bot. Surv. India 4 77-88 Ramayya N 1975 Trichomes of angiosperms: Structure and-classificat.ion (Abstractl in Forro structure andfunction in plants (Sardar Patel University: India: AII India symposium) Sabnis T S 1920 The physiological anatomy of the plants of the lndian desert; J. lndian Bot. Soc. l 237-246 Shah G L and Kothari M J 1973 On the structure of stomata and hairs and its bearing on the systematics of the tribe vicieae (Papilionaceaet; Flora Bd. 162 533-548 Trichomes of Papilionoideae in relation to taxonomy 441 S hah G L and Kothari M J 1975 Obsr on stomata and hairs on vr and floral organs in the tribe Trifoliear Aust. Z Bot. 23 ! 11-122 Solereder H 1908 Systematie anatomy of the dieotyledons Vol.l (London: Oxford Univr Presa) Theobald W L, Krahulik J L and Rollins R C 1979 Trichomr deseription and e lassifieation; in Anatomy o/the dicotyledons (eds) C R Mr andL Chalk (Oxford: Clarr Press) Uphof J C Th 1962 Plant hairs in Encyclopedia o•plant anatomy (ed.) K Linsbauer (Bcrlin:Gertbrudcr Borntraegr Wr A 1867 Dir laflanzenhaarr Karesten Bot. Unters. 1 369-677 Figures 1-25. Trichomes of Papilionoidcar i. Abrus precatorius: Unicellular conical hair from sepal margins 2,17,21-23. Cicer arietinum: 2. Unicellutar cylindrical hair from sepal margins 17. Uniseriate filiform cylindrieal hair from wing petal margin 21,22. T S of head and stalk of uniseriate filiform ovalis-capitate hair from T S stem respectively 23. Uniseriate fi[iform ovalis-capitate hair from L S Ieaflet 3,4. Alysicarpus rugosus: Uniseriate filiform capitatr hair and T S body of the hair from lea/respectively 5.15. Atylosia scarabaeoides: Uniseriate filiform capitate and uniseriatr filiform vesi- cular clavate hairs from leaflet respectively 6. Pongamia pinnata: Uniseriate filiform clavate hair from leaflet 7. Melilotus alba: Uniseriate fitiform clavate hair from leaflet Vigna cylindrica: Uniseriate filiform capitate and unisr macroform pricklr hairs from leaflet margin respectively 9,16.,240 Alysicarpus hamosus: 9. Unisr fili- forro obpyriform hair from sepal margins 16.24. Uniseriate filiform uncinate and uniseriatr macroform uncinate hairs from ovary respectivr 10. Desmodium triflorum: Uniseriate filiform obpyriform hair from ovary 11. Alysicarpus monilifer: Uniseriate filiform obpyriform hair from lea/ abaxial 12. Cajanus cajan: Uniseriate filiform obpyriform hair from leaflet adaxiat 13,18 Medicago sativa: Uniseriate filiform cylindr{c- clavate and uniseriate filiform cylindrical hairs respectively from sepal adaxia114. Rhyn- chosia aurea: Uniseriate filiform obpyriform hair from stem 11,12. Stylosanthes fruti- cosa: Uniseriate filiform flagellete hair from leaflet and sepal rnargins respectively. Abbreviations: B, body; F, foot; H, head; S, stalk; V, vesicte. Fi 26-43. Trichomr of Papilionoideae 26. Phaseolus aconiti/olius: Uniseriate macroform conical hair from stem 27,35. Mucuna pruriens: Uniseriate macroform conieal hairs from petiolule and sepal margins respectively 28. Heylandia latebrosa: Uniseriate macroform conical hair from leaflet margin 29,30,31. Arachis hypogaea: 29. Uniseriate maeroform conical hair from stipule margin 30,31. Uniseriate filiform conical hairs from stipule margins 32. Desmodium triflorum: Uniseriate macroform conieal hair from leaflet margin; 33. Atylosia scarabaeoides: Uniseriate macroform conical hair from leaflet 34. Medicago sativa: Uniseriate macroform conicat hair from stipule margin 36. Crotalaria ramosissima: Uniseriate macroform eonical hair from stem 37. Derris scandens: Uniseriate macroform cylindric-clavate hair from peduncle 38. Erythrina orientalis: Uniseriate macroform stellate hair from ovary 39. Vigna cylindrica: Uniseriate macroform conical hair from petiolule 40. Crotalaria verrucosa: Uniseriate macroform conicat hair from stem 41. Dalbergia sissoo: Multiseriate ovate hair from L S stipule 42,43. Stylosanthesfruticosa: 42. Diagrammatic representation of the multiseriate ventricose hair 43. Multiseriate ventricose hair from leaflet margin. Abbreviations: B, body; E, emergence: F, foot; H, head; S, stalk.