Botanical Survey of India | Flora of India

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ASTERACEAE
nom. cons.



Herbs, annual or perennial, sometimes shrubs or climbers, rarely arborescent, often with stolons, rhizomes, tubers or fleshy roots, variously pubescent or glandular, rarely laticiferous. Leaves alternate or opposite) sometimes radical, simple or sometimes 2 to many foliate, entire to variously dissected; stipules absent. Flowers actinomorphic or zygomorphic, hermaphrodite, unisexual or neuter, 1 to numerous, aggregated on a common receptacle, enclosed by a common involucre of bracts (phyllaries) forming the heads or capitula. Phyllaries in one or more series, free or connate, valvate or imbricate, green or coloured, herbaceous or scarious. Capitula sessile or peduncled, variously arranged spikes, corymbs, panicles or rarely in glomerules; .homogamous or heterogamous or sometimes monoecious, discoid (all florets alike, perfect and have tubular corolla) or ligulate (all florets perfect but with ligulate corolla; ligules conspicuous) or disciform (outer florets filiform, pistillate; ligules inconspicuous) or radiate (ray florets on the periphery, either neutral or pistillate and disc florets on the rest of the receptacle). Receptacle flat, convex, concave or conical, paleaceous or naked. Calyx absent or reduced to pappus of bristles, awns or scales. Corolla sympetalous, of 4 - 5 petals, tubular, ligulate or bilabiate. Stamens 5 or rarely 4, epipetalous, alternating with corolla lobes; anthers 2-loculed, connate (syngenesious) forming a tube around the style, oblong, introrse with sterile tips, obtuse or sagittate or caudate and tailed at base, dehiscing lengthwise. Style branches 2, filiform or broader, appendaged or not. Ovary inferior, unilocular, terete or compressed; ovuie solitary. Fruit an achene (Cypsela), variously ridged and grooved or striate, smooth of with ornamentations, often crowned by the persistent pappus. Pappus in one or more series, simple or feathery, often replaced by bristles, awns or scales. Seeds exalbuminous.

The family constitutes the largest vascular plant family with ca 30,000 species and over 1100 genera. Although the family is well represented in temperate or subtropical regions, the species have adopted to varied ecological conditions. In lowland areas, a large number of species have become adventive. In India, the family is represented by ca 900 species under 167 genera. The species are distributed widely along sea coasts, cultivated fields, alpine areas in Himalayas and in cold deserts of Ladakh and Lahul-Spiti. A vast majority of them are recent introductions and some obnoxious weeds in the agriculture fields are Eupatorium spp., Mikania micrantha, Parthenium hysterophorus, Ageratum conyzoides. A. houstonianum, Tagetes minuta, Acanthospermum hispidum, Xanthium indicum and a few others.

Economically the family is important as the source of Sunflower and Safflower oil. Many are useful in native medicines. Several ornamental taxa belonging to Chrysanthemum. Dahlia, Cosmos, ragetes, Calendula, Zinnia and a few others are popular throughout the world.

Asteraceae form a distinct group whose phylogenetic relationship within the family as well as with other families are not clearly established. Many consider that Asteraceae are allied to both Campanulales and Calycerales (Takhtajan , 1980). Based on palynological evidences (Skvarla et al. 1977) the family is said to be closely related to Calyceraceae. According to Cronquist (1981) the Calyceraceae can be no more than 'Collateral allies' of Asteraceae. The family differs from Campanulaceae in having flowers aggregated into capitulum surrounded by involucral bracts, connate anthers, the 2-lobed or 2-fid style, definite number of carpels and ovules and nonendospermous seeds. Therefore, derivation of Asteraceae from Campanulaceae stock is also ruled out.

Rubiales have also been considered as a possible ancestral group by Cronquist (1981). But Asteraceae are quite distinct chemically as well as morphologically. According to Cronquist (1981) the ancestry of Asteraceae probably lies in or near the Rubiaceae, along a line parallel in some respects to the line leading to the Dipsacales and Calycerales.

Within the family, the phylogenetic relationship among the various tribes is also no~ clear. Some authors consider Heliantheae as the most primitive tribe (Cronquist, 1958). Yet others consider Vemonieae, Mutisieae, Senecioneae as the primitive tribes. In the present treatment of the family Bentham & Hooker's (1873) arrangement of tribes is broadly followed, except for tribe Tageteae which has been treated as a distinct tribe.

Literature. BENTHAM, G. (1873). Notes on the classification, history and geographical distribution of Compositae. J. Linn. Soc. Bot. 13: 335 - 577. BENTHAM, G. & J.D. HOOKER(1873). Compositae. Genera Plantarum 2: 163 - 533. CARLQUIST, S. (1976). Tribal interrelationships and Phylogeny of the Asteraceae. Aliso 8: 465-492. CLARKE. C.B. (1876) compositae Indicae, London. CRONQUIST, A. (1955). Phylogeny and Taxonomy of the Composilae. Am. Midl. Nat. 53: 478 - 511. CRONQUIST, A. (1977). the compositae revisited. Brittonia 29: 137 - 153. CRONQUIST, A. (1981). An integrated system of classification of flowering plants. p.p. 1262. New York. HEYWOOD, V.H., J.B. HUBOURNE & B.L. TURNER (1977). The Biology and chemistry of the compositae 2 vols. Academic Press, London. HOFFMAN, O. (1894). Compositae in Engler & Prantl. Nat. Pflanzenfam. IV. 5: 87 - 387. HOOKER, J.D. (1881). Compositae in Flora of British India 3: 219 - 419. RAO, R.R. et al. (1988). Florae Indicae Enumeratio-Asteraceae. Bot. Surv. India, Calcutta. SKVARIA, J.J., B.L. TURNER, V.C. PATEL & A.S. TOMB (1977). Pollen morphology in the compositae and in morphologically related families. In V.H. HEYWOOD & J.B. HAUBOURNE (eds.) The Biology and Chemestry of Compositae 1: 141 - 259. Academic Preas London. SMALL, J. (1917-1919). the origin and development of the compositae. New Phytol. 16: 157 - 177, 198 - 221, 253 - 276; 17: 13 - 40, 69 - 94, 114 - 142, 200 - 230; 18. 1 - 35, 65 - 89, 129 - 176, 201 - 234. SOLBRIG, O.T. (1963). Subfamilial nomenclature in Compositae. Taxon 12: 229 - 235. SOLBRIG, O.T. (1963). The Tribes of Compositae in the Southeastern United Slates. J. Arn. Arb. 44: 436 - 461. TAKHTAJAN, A. (1980). Outline of the classification of Flowering Plants (Magnoliophyta) Bot. Rev. 46: 225 - 359. Columbia Univ. Press, New York. WAGENITZ, G. (1975). Systematics and Phylogeny of the Compositae (Asteraceae) Pl. Syst. Evol. 125: 29 - 46.



KEY TO THE TRIBES


1a. Capitula homogamous; florets all ligulate or tubular or tubuliform 2
b. Capitula heterogamous; florets both ray and Disk 10
2a. Florets all ligulate (florets all ligulate in calamiris but achenes silky, villous.) Tribe 5. CICHORIEAE
b. Florets all tubular 3
3a. Anther cells tailed or auricled or mucronate at the base 4
b. Anther cells cleft at base or subentire 5
4a. Styles subentire or arms short, hairy or thickened towards the base; leaves mostly spinous margined Tribe 4. CARDUEAE
b. Style branches of hermaphrodite florets truncate or appendaged; leaves never spinous margined Tribe 10. SENECIONEAE
5a. Leaves opposite Tribe 6. EUPATORIEAE
b. leaves alternate 6
6a. Florets all tubular; style branches subulate, hairy Tribe 12. VERNONIEAE
b. Florets all tubuliform; style branches linear, obtuse, truncate or appendiculate 7
7a. Anther cells tailed or auricled 8
b. Anther cells not tailed 9
8a. Style arms linear, obtuse or styles of sterile florets undivided Tribe 8. INULEAE
b. Style arms of hermaphrodite florets truncate or appendaged Tribe 10. SENECIONEAE
9a. Involucral bracts 2-many-seriate, dry or with scarious tips Tribe 1. ANTHEMIDEAE
b. Involucral bracts uniseriate, herbaceoul or foliaceous Tribe 7. HELIANTHEAE
10a. Achenes large, thick and curved, often deformed; pappus absent Tribe 3. CALENDULEA E
b. Acbenes not as above; pappus various or absent 11
11a. Anthers distinctly tailed 12
b. Anthers not tailed, sometimes mucronate at the base 14
12a. Anther tips without distinct hyaline appendage Tribe 9. MUTISIEAE
b. Anther tips with distinct hyaline appendage 13
13a. Style branches linear, obtuse, non appendiculate Tribe 8. INULEAE
b. Style branches of hermaphrodite florets, truncate or appendiculate Tribe 10. SENECIONEAE
14a. Involucral bracts with scarious or hyaline margins and tips 15
b. Involucral bracts not as above 16
15a. Receptacle epaleaceous. Pappus hairs capillary Tribe 2. ASTEREAE
b. Receptacle paleaceous. Pappus of scales and paleas or absent Tribe 1. ANTHEMIDEAE
16a. Involucral bracts uniseriate, valvate, connate nearly to apex Tribe 11. TAGETEAE
b. Involucral bracts 1-many seriate, not connate as above 17
17a. Pappus of white, copious, capillary hairs (paleaceous in Seneciograhomi and S. belgamensis, but leaves white tomentose beneath with prominent venation) Tribe 10. SENECIONEAE
b. Pappus of paleas, bristles or awns, rarely absent Tribe 7. HELIANTHEAE


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