678 



BOTANY 



PAKT II 



pinnate, terminal spine and a felt of liairs. ilarginal florets sterile. Pappus 

 double. Centaurea with dry, scaly involucral bracts and large, sterile marginal 



Horets. On the irritability of the stamens cf. Fig. 241 



and p. 324. 



{b) Euitatorieac. Flowers hermaphrodite. Receptacle 



■without floral bracts. Involucral leaves herbaceous. 



Eupatorium cnnnabinum (British). Aggeratum mcxicanum, 



commonly cultivated. 



2. Lahiatiflorae. Mutiseae occur in tropical America. 



3. Liguliflorac. Cichorieae with onlj' zygomorphic, 

 ligulate, florets with a five-toothed corolla in the flower- 

 head. All the flowers are hermaphrodite. Laticiferous 

 vessels in all organs of the plant. Taraxacum officinale 

 (Dandelion, Fig. 734) is a common plant throughout 

 the northern hemisphere. It has a long, carrot-shaped 

 tap-root, a rosette of coarsel}- toothed leaves, and terminal 

 inflorescences, borne singly on hollow stalks (apogamy, 

 cf. p. 514). Fruits wilh an elongated beak, carrying 

 i;p the pappus as a stalked, umbrella-shaped crown of 

 hairs (Fig. 732). Lactuca saliva, Lettuce. L. virosa, 

 a herbaceous plant of considerable height with a branched 

 stem, sessile sagittate leaves and numerous, small, few- 

 flowered inflorescences grouped in panicles. Fruits like 

 those of Taraxctciim. L. Scariola (*), Compass plant, 

 has leaves which take a vertical position. Cichorium 

 Intyhus (Chicory), C. endivia, Endive, with heads of 

 blue flowers ; pappus of short erect scales (Fig. 731 C). 

 Tragopogon and h'corzoncra have a feathery pappus ; 

 Sc. Jdspanictt. Crcpis has a soft, flexible, hairy pappus 

 of brownish colour. Sonchtis, pappus of several series 



of bristles. Ricracium (*^), a large European genus with many forms. (Apogamy 

 and aiJospory, cf p. 514.) Pappus white, rigid, and brittle (Fig. 731 B). 



Fig. 730. — Androeciuiu of 

 Carduus crisiius (x 10). 

 (After Baillon.) 



\li||/fe^^^ 



Fii;. 731. — Fruits of — A, Ihliantlius annuns : B, Hicrtwium virosttm ; C, Cichorium 

 Intyhus. (After B.MLLON.) 



4. Diver siflorac. Two distinct types of flower or flowers of distinct sexes in 

 the capitulum. 



(a) Aslcrcac, receptacle naked, without floral bracts. Involucral bracts, numer- 

 ous, imbricate. Hermaiihrodite tubular flowers in centre, surrounded l)y one- 

 lipped ray-florets. Pajipus as a rule of liristle-like hairs. Style with straight 



