Botanical Survey of India | Flora of India

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Shrubs or herbs, rarely trees or climbers, scabrous or silky villous. Leaves opposite or sometimes alternate near the inflorescence, simple or compound, entire, toothed, lobed or dissected, petioled or sessile. Inflorescence scapose, paniculate or often of solitary, long-stalked terminal heads. Bracts and bracteoles present. Heads usually radiate, sometimes discoid, rarely disciform, monoecious. Involucral bracts few to many, usually leafy, sometimes dry, hard or membranous, generally biseriate or rarely multiseriate. Receptacle paleaceous , sometimes epaleaceous, flat or conical; pales usually flat or concave or enfolding the florets, occasionally tightly enveloping the achenes. Ray florets mostly yellow; corolla ligulate, rarely tubular or reduced, 2 - 3 denticulate or entire. Disc florets with 4 - 5 lobed, campanulate corolla. Anthers obtuse at the base, not tailed, with a terminal appendage, distinct or scarcely coherent in some genera. Ovary often compressed, often with a cupular nectary; style truncate or appendiculate to subulate, with or without appendages. Achenes thick, flattened, terete or 3 - 4 angled or winged. Pappus of scales, awns, bristles or pales or absent.

The tribe Heliantheae is generally considered as the most primitive tribe of the family on account of the opposite leaves, solitary or few large heads, leafy involucres, chaffy receptacles, carpellate ray and bisexual disc florets, tailless anthers, style branches without distinct stigma, etc. The species of the tribe have remarkable adaption to varied ecological conditions.

Bentham (1873) divided the tribe into 10 subtribes. Hooker (1881) while treating Compositae in Flora of British India mentioned 7 sub tribes viz., Lagasceae, Millerieae, Melampodieae, Ambrosieae, Verbesineae, Coropsideae, and Galinsogeae. As the distinguishing characters of these subtribes are more or less overlapping, the tribe is treated without any divisions.

Predominantly distributed in tropical, subtropical and temperate regions; ca 300 genera, 27 genera and 56 species in India.

Literature. BENTHAM. G. (1873). Notes on the classification, history and geoaraphical distribution of Compositae. J. Linn. Soc. Bot. 13: 335-577. BENTHAM, G. & HOOKER, J.D. (1873). Genera plantarum 2: 163-533. CRONQUIST, A. (1955). Phylogeny and taxonomy of the Compositae. Arn. Midl. Nat. 53: 478-511. SOLBRIG, O.T. (1963). The Tribes of Compositae in Southern United States. J. Arn. Arb. 44: 436-461. WODEHOUSE, R.P. (1928). Pollen grains in the identification and clallification of plants. I. The Ambrasiaceae. Bull. Torrey Bot. Club 55: 181-198. 6. WOODSON, R.E. Jr. & SCHERY, R.W. (1975). Fl. Panama: Compositae. Ann. Miss. Bot. Gard. 62: 835-1321.



KEY TO THE GENERA


1a. Heads non-glomerulate. more than one flowered 2
b. Heads in terminal glomerules. one flowered 27
2a. Heads unisexual 3
b. Heads bisexual 4
3a. All leaves alternate; involucre in fruit with straight or hooked spines and distinct beak 27. Xanthium
b. At least some leaves opposite; involucre in fruit with small spines or tubercles near the apex 3. Ambrosia
4a. Receptacle epaleaceous 2. Adenocaulon
b. Receptacle paleaceous 4
5a. Leaves divided to the base or deeply pinnatifid 5
b. Leaves simple or pinnately compound 7
6a. Achenes linear, with retrorsely barbed pappus awns 4. Bidens
b. Achenes somewhat rounded. without retrorsely barbed pappus awns 18. Parthenium
7a. Ray achenes only fertile; epappose 8
b. Ray achenes sterile or fertile; disc achenes always fertile; pappose or epappose 9
8a. Achenes trigonous or laterally compressed. covered with hooked bristles 1. Acanthospermum
b. Achenes flat, dorsally compressed, smooth, with a short neck at the apex 17. Moonia
9a. Disc achenes rounded or laterally compressed; pappus absent or of 2 short, weak scales 10
b. Disc achenes dorsally compressed or angular; pappus present or absent 19
10a. Outer involucral bracts clavate, spreading; inner ones enclosing the achenes 11
b. Outer involucral bracts erect; inner ones not enclosing the achenes 12
11a. Outer involucral bracts prominently glandular; terrestrial herbs 20. Siegesbeckia
b. Outer involucral bracts, eglandular; marshy herbs 9. Enhydra
12a. Receptacle flat, never conical 13
b. Receptacle convex or conical 18
13a. Pales brittle like 7. Eclipta
b. Pales linear or oblanceolate, concave or folded 14
14a. Shrubs or small trees; pales accrescent 16. Montanoa
b. Herbs; pales not accrescent 15
15a. Pales obtuse, lacerate; flowers white; pappus of 2 weak awns 5. Blainvillea
b. Pales acute, entire; flowers yellow; pappus present or absent 16
16a. Pappus absent or of 2 minute scales 23. Tithonia
b. Pappus of 2 scale. with numerous minute scales in between 17
17a. Heads always erect, solitary or few in loose corymbs 26. Wedelia
b. Heads cernuous after anthesis, solitary or in pain on short axillary peduncles 8. Eleutheranthera
18a. Heads heterogamous; receptacle convex; achenes enclosed in hardened, pointed palea 19. Sclerocarpus
b. Heads homogamous; receptacle conical; achenes naked 21. Spilanthes
19a. Pappus absent, if present of 2-3 bristles or awns 20
b. Pappus consisting of 5 or more bristles or scales 26
20a. Achenes compressed 21
b. Achenes fusiform, angular 23
21a. Margins of achenes laciniate-winged; pappus of 2 unbarbed awns 22. Synedrella
b. Margins of achenes not laciniate winged 22
22a. Pappus awns present 25. Verbesina
b. Pappus awns absent 14. Guizotia
23a. Pappus awns not retrorsely barbellate 12. Glossocardia
b. Pappus awns retrorsely barbellate 24
24a. Medium sized to tall herbs; leaves cauline; style branches short, subulate 4. Bidens
b. Small herbs; leaves basal, rosulate; style branches with long, villous appendages 25
25a. Achenes with 2 tetrosely barbed pappus awns 13. Glossogyne
b. Achenes without pappus awns 6. Chrysanthellum
26a. Erect, annual herbs; pappus of short fimbriate scales, about 1 mm long 11. Galinsoga
b. Prostrate, ascending, perennial herbs; pappus of fine plumose bristles, about 5 mm long 24. Tridax
27a. Heads homogamous 15. Lagascea
b. Heads heterogamous 10. Flaveria


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