1950 A TEXTBOOK OF THEORETICAL BOTANY 



after fertilization be carried up on a tubular stalk. It is frequently hygro- 

 scopic. 



The seed is non-endospermic and completely fills the fruit, its coat 

 being fused with that of the pericarp. The embryo is straight with a short 

 radicle and flat or semi-circular cotyledons. 



According to Willis the family contains 900 genera and over 13,000 

 species, with a world-wide distribution. 



The anatomical features of the family are worthy of note, particularly the 

 frequent occurrence of schizogenous canals in stem, root and leaf, which are 

 widely distributed in the different tribes of the Tubulifloreae, while latici- 

 ferous vessels occur in the Cichorieae. 



The family has been variously divided up by different authors and here 

 we shall adopt the system proposed by Hoffmann. 



I. Tubulifloreae 



Corolla of disc florets never ligulate. Laticiferous vessels absent but 

 schizogenously produced oil canals often present. 



1. Vernonieae. Capitulum homogamous, florets tubular, regular, with 



five narrow lobes, never yellow in colour. Anthers arrow-shaped 

 at the base, pointed or rarely tailed, with filaments inserted high 

 above the base. Style generally divided into two long, pointed 

 stigmas, hairy on the outside. Pappus usually copious and setose. 

 Vertwnia and Elaphantopus. 

 The members may be herbs, trees or shrubs usually with alternate 

 leaves. They occur mostly in tropical America though some are 

 found in Africa and Asia. The tribe is not represented in Europe. 



2. Eupatorieae. Capitulum homogamous, corolla tubular and regular, 



with five short teeth, never pure yellow in colour. Anthers 

 blunt at the base and basifixed. Stigmas long but blunt or 

 flattened at the tip, covered with very short hairs. Pappus of 

 five or more bristles or scales, but sometimes absent. Eupatorium, 

 Mikania and Adenostemma. 

 The members of the tribe are herbs or shrubs which occur chiefly 

 in the New World, though Eupatorium cannabitium (Hemp Agri- 

 mony) is British. Species of Mikania occur mostly in Brazil 

 where some are climbers. 



3. Astereae. Capitulum heterogamous or homogamous, with female or 



sterile ray florets and bisexual or male disc florets. All or nearly 

 all central flowers tubular. Anthers blunt at the base and basi- 

 fixed. Stigmas flattened, with marginal rows of papillae and 

 terminal hairy sterile portions. Bellis, Aster, Olearia, Soltdago, 

 Erigeron, Baccharis, CoUistephns and Conyza. 

 The plants are mostly herbaceous, world-wide in distribution, 

 though more common in the New World than the Old World, 

 and more typical of temperate than tropical regions. We shall 

 discuss certain points about this tribe later. 



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