570 DICOTYLEDONES. 



suckers. Cynara (Artichoke) has a feathery pappus and large, 

 solitary capitulum, with broad involucral leaves ; these have a 

 fleshy base like the receptacle (edible). Silylum has united fila- 

 ments. S. marianum (Milk - thistle), has leaves with numerous white spots. 

 Onopordon (Cotton-thistle). Cnicus (C. benedictus) has a large, many-spined 

 thorn on the involucral leaves; pappus trimorphic. Lappa (Burdock) is 

 easily recognized by the hooked involucral leaves, which assist in the 

 distribution of the fruit ; in this respect it differs from the other 

 inflorescences, and also in the fact that the pappus is short, and 

 quickly falls off, without serving as a means of distribution. 

 Carlina ; the external involucral leaves are leafy, thorny, with branched or un- 

 branched spines standing straight out or bent backwards ; the internal ones are 

 dry, and prolonged as dry, coloured, radiating scales. The well-developed 

 bristles on the receptacle and edge of the calyx are deeply cleft and lobcd. 

 Centaurea (Knap-weed, Fig. 607). The ray-flowers are neuter, 

 and generally larger than the disc-flowers ; the involucral leaves 

 are regularly imbricate, but are frequently provided at the apex 

 with a dry, chaffy, often lobed, fringed appendage. The attach- 

 ment of the fruit is lateral. Serratula (Saw-wort). Carthamus, the 

 outer and inner involucral leaves differ very much. Echinops (Globe- thistle) 

 is characterised by having " compound capitula," i.e. there is only 

 one flower in each capitulum, but many such capitula are collected 

 into a spherical head, which at the base may also have a few 

 involucral leaves. The individual capitula have narrow, linear 

 involucral leaves. (There are altogether about 150 species of Compositae 

 with 1-flowered capitula, all from warm countries.) Xeranthemum, IStaelie- 

 lina, Jurinea, Saussurea, etc. 



2. Mutisieae, Labiate-flowered Group. Tropical (S. American) forms 

 whose zygomorphic flowers have a bilabiate corolla (|). *The involucre is 

 nearly the same as in the Thistles. 



3. Cichorieae, Chicory Group (or LIGULJFLOR^). The flowers 

 are all and have a ligulate, ^-dentate corolla. The stylar branches 

 are thin and prolonged (Fig. 609 J5). Laticiferous vessels occur in 

 the majority (in this feature they resemble the Lobeliacene and 

 Campanulacea3). 



A. The pappus is wanting, or it is scale-like, but not long and 

 hairy. Cichorium (Chicory) ; capitula with blue flowers, borne 

 singly or a few together in the leaf-axil ; there are two whorls of 

 involucral leaves, an outer one of short and radiating, an inner 

 of more numerous, longer and erect leaves ; pappus, scale-like. 

 Lapsana (Nipplewort). The few involucral leaves are nearly 

 of the samesize, and persist forming a sort of capsule round the 



