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LII. COMPOSITE 
The naming of a composite plant will be facilitated if attention 
is paid to the following points : — 
1. Whether the heads are simple or compound. 
2. Whether the heads are discoid, radiate or ligulate. 
3. The character of the pappus or its absence. 
4. The colour of the flowers. 
5. The character of the achenes. 
6. The character of the leaves and involucral bracts. 
7. The characters of the receptacle, whether flat or not, 
whether naked or not, and the nature of the bristles or scales if 
present. 
Abstract of the Key to the Genera 
A. Simple heads, subdivided into 
I. Discoid heads ; flowers all tubular. 
II. Radiate heads ; ray-flowers ligulate, disk-flowers tubular. 
III. Ligulate heads ; flowers all ligulate. 
B. Compound heads, includes only 3 genera. 
A. Simple heads 
I. Discoid heads 
* Pappus of hairs 
Flowers purple or red (white in Eujoatorium). 
Involucral bracts not spiny. Leaves not prickly. 
Receptacle naked. 
Leaves alternate. 
Involucral bracts in several series, unequal. 
Stems naked .1. 
Stems winged 14. 
Involucral bracts in one series, equal . . .37. 
Leaves opposite or whorled. Flowers white . . 4. 
Receptacle bristly. 
Pappus feathery 43. 
Pappus minutely barbed 44. 
Involucral bracts spiny. 
Leaves not prickly or spiny . . . . .40. 
Leaves prickly. 
Stems winged. Pappus not feathery . . .41. 
Stems not winged. Pappus feathery . . . 42. 
Flowers yellow (sometimes white in Cnicus). 
Involucral bracts spine-tipped. 
Spines short. Pappus feathery ..... 42. 
Spines long, needle-like. Pappus not feathery . . 45. 
Involucral bracts not spine-tipped. 
Involucral bracts green. 
Style-arms short. 
Herbs. 
Anther-cells tailed 13. 
Anther-cells not tailed 12. 
Vernonia. 
Laggera. 
■Emilia. 
Enpatorium. 
Saussurea. 
Serratula. 
Arctium. 
Carduus. 
Cnicus d 
Cnicus . 1 2 
Tricholepis. 
Blumea. 
Conyza. 3 
1 C. arvensis only. 2 C. argyracanthus and C. Wallichii, former some- 
times has white flowers. 3 Except C. stricta, which has minutely radiate 
heads. 
