682 



BOTANY 



in numbers. Lappa (Burdock), involucral bracts with recurved, hook-like tips 

 (Fig. 769 a). Cynara Scolymus (Artichoke). Cnicus benedictus (Fig. 774), capit- 

 ula solitary, terminal, surrounded by foliage leaves. In- 

 volucral bracts with a large, sometimes pinnate, terminal 

 spine and a felt of hairs. Marginal florets sterile. 

 Pappus double. Centaurea with dry, scaly involucral 

 bracts and large, sterile marginal florets. On the irrit- 

 ability of the stamens cf. Fig. 238 and p. 296. 



(b) Eupatorieae. Flowers hermaphrodite. Receptacle 

 without floral bracts. Involucral leaves herbaceous. 

 Eupatorium cannabinum (British). Aggcratum mexi- 

 canum, commonly cultivated. 



2. Labiatiflorae. Afutisieae occur in tropical America. 



3. Liguliflorae. Cichorieae with only zygomorphic, 

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

 head. All the flowers are hermaphrodite. Laticiferous 

 vessels in all organs of the plant. Taraxacum ojficinale 

 (Dandelion, Fig. 775) is a common plant throughout 

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

 tap-root, a rosette of coarsely toothed leaves, and terminal 

 inflorescences, borne singly on hollow stalks (apogamy, 

 cf. p. 518). Fruits with an elongated beak, carrying 

 up the pappus as a stalked, umbrella-shaped crown of 

 hairs (Fig. 773). Lactuca sativa, Lettuce. L. virosa, 

 a herbaceous plant of considerable height with a branched 

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



of flowered inflorescences grouped in panicles. Fruits like 

 those of Taraxacum. L. Scariola C 52 ), Compass plant, 

 has leaves which take a vertical position. Cichorium 

 Intybus (Chicory), C. endivia, Endive, with heads of blue 



flowers ; pappus of short erect scales (Fig. 772 C). Tragopoyon and Scorzoncra have 

 a feathery pappus ; Sc. hispanica. Crepis has a soft, flexible, hairy pappus of 

 brownish colour. Sonchus, pappus, of several series of bristles. Hieracium ( M ), 



Fn;. 771. Androecimii 

 Carditus crispiis (x 10). 

 (After BAILLON.) 



7? 



Fio. 772. Fruits of A, Helianthvs a unit us ; Ji, Hieracium virosum ; C, 

 Intybus. (After BAILLON.) 



a large European genus with many forms. (Apogamy and apospory, cf. p. 517.) 

 Pappus white, rigid, and brittle (Fig. 772 B). 



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

 capitulum. 



