THE DICOTYLEDONES 



1947 



jacobaea), Oxeye Daisy (Chrysanthemum leiicanthemum) and Mugwort 

 {Artemisia vulgaris). Several are commonly grown as vegetables, such as 



Fig. 1877. — Taraxacum officinale. Dandelion. Capi- 

 tulum in which all the flowers except a few in the 

 centre have liguliform, i.e., strap-shaped, exten- 

 sions of the corolla. 



Chicory {Cichorium intyhus), Lettuce (Lactuca), Salsify {Tragopogon porri- 

 foliutri), or as herbs, such as Tansy [Tanacetum vulgare) and Wormwood 

 [Artemisia absinthium). IVIany common garden flowers are represented by 

 species of the family and we can do no more than cite a few common 

 examples: Michaelmas Daisies [Aster), C\\vys2inx\itvaum?, [Chrysanthemum), 

 Sunflowers [Helianthus), Cornflowers [Centaurea), Golden Rod [Solidago) 

 and Everlastings [Helichrxsum). 



The plants are herbaceous or shrubby, rarely trees, usually with alter- 

 nate leaves. Stipules are absent. There is great diversity of form. Senecio, 

 which is the largest genus, having over 2,500 species, besides including 

 annual and perennial herbs, may be a climber, as S. macroglossus in South 

 Africa; a shrub, as S. hastata, found in the Mediterranean region; a 

 tree, as S. johnstonii in Central Africa; a succulent, as S. orticulata 

 found in South Africa, and a marsh plant, as S. aquatica in this 

 country. True water plants are rare in the family, though Hutchinson 

 mentions four species, widely separated both in systematic position 

 and also in geographical distribution, which suggests that an aquatic 

 habit has recently developed independently several times in the 

 family. These four species are all small herbs with slender stems and 

 much dissected submerged leaves. 



There is frequently a tap-root, which may bear adventitious buds, as in 

 the Dandelion, where they serve as a means of rapid propagation. Alter- 



