598 



BOTANY 



Flowers actinomorphic or the ray-flowers one-lipped, no latex. (A) Cynareae. 

 Receptacle with setaceous paleae, involucral leaves either prickly or with 

 membranaceous margins, style swollen below the stigmas into a cushion-like ring, 

 fruit with pappus. Carduus (Plumeless Thistle), involucre prickly, hairs of pappus 

 naked ; Oirsium (Common or Plumed Thistle), like the preceding, but with 

 feathery pappus ; Cnicus (Blessed Thistle) ; Lappa (Burdock), tips of involucral 

 leaves hooked ; Centaurea, involucral leaves with bristles or membranous margins, 



ray-flowers, neuter. (B) Eupatorieae. Flowers 

 actinomorphic, involucre herbaceous, receptacle 

 without paleae, style not swollen below the 

 stigmas ; Petasites (P. vulgaris, the Butter-bur) ; 

 Tussilago (Coltsfoot) ; Eupatorium (Thorough- 

 wort). (0) Astereae. Marginal flowers female, 

 usually zygomorphic. (a) Anthemideae, with- 

 out pappus ; Anthemis (Chamomile) and 

 Achillea (Milfoil, Yarrow), with paleae ; Matri- 

 caria (Wild Chamomile) and Chrysanthemum, 

 without paleae ; Artemisia ("Wormwood), with 

 tubular flowers only. (6) Heliantheae ; Seli- 

 anthus (Sunflower), (c) Calenduleae ; Calendula 

 (Marigold). (d) Senecioneae, pappus hairy ; 

 Senecio (Groundsel) ; Arnica. J(e) Astereae, 

 pappus bristle-like, frequently brown ; Aster ; 

 Solidago (Golden-rod) ; Erigeron (Fleabane); 

 Inula (Elecampane) ; Gnaphalium (Cudweed) ; 

 Antennaria (Everlasting Cat's-foot) and Beli- 

 chrysum, with scarious involucre, (f) Arribro- 

 sieae, anthers free ; Xanthium (Cocklebur). 

 (2) Labiatiftorae. Flowers bilabiate. The 

 majority of the plants in this group are native 

 of South America ; none occur in Europe. (3) 

 Liguliflorae. Flowers ligulate. Mostly herbs 

 with septated latex-tubes. Taraxacum (Dande- 

 lion), with beaked fruit, pappus of unbranched 

 hairs ; Lactuca (Lettuce) ; Crepis (Hawk's- 

 beard) ; Sieracium (Hawkweed), with brownish 

 pappus of unbranched hairs ; Sonchus (Sow- 

 Thistle) ; Scorzonera and Tragopogon ( T. porri- 

 folius, Salsify), with feathery pappus ; Leon- 

 todon (Hawkbit). 

 The Compositae form the largest family of the 

 vegetable kingdom, comprising from 10,000 to 12,000 species, scattered over thewhole 

 world. The following are important on account of their special economic value. 

 Lactuca sativa (Lettuce), Cichoriwm Endivia (Endive), C. Intyius (Chicory), 

 Cynara Scolymus (Artichoke), Scorzonera hispanica (Viper's - grass), Artemisia 

 Dracunculus (Tarragon). Ornamental plants : Dahlia variabilis (Dahlia), various 

 species of Aster and Chrysanthemum, Helianthus annuus (Common Sunflower), 

 Calendula officinalis (Pot-Marigold). 



Poisonous. — Lactuca virosa (Fig. 594), a tall glabrous herb over 1"50 metre 

 high, with elongated amplexicaul leaves and small yellow-flowered capitula in 

 corymbs. The achenes are black and have a white pappus. The whole plant is 



Fig. 594. — Lactuca virosa (£ nat. size). 

 Poisonous and Officinal. 



Geographical Distribution.- 



