310 LXXV. COMPOSITiE. 



tivated for the use of the clothiers {fullonum), who employ th6 heads with their 

 hard, hooked scales to raise the nap upon woollen cloths. For this purpose 

 they are fixed around the circumference of a revolving drum. Flowers in July. :|: 



2. SCABIOSA. 



Lat. scabies, leprosy ; planU said to be useful in cutaneous diseases. 



Flowers in heads ; involucre many-leaved ; involucel nearly cylin- 

 drical, with 8 little excavations ; calyx limb consisting of 5 setce, 

 sometimes partially abortive. — %■ Large^ mostly European herbs with 

 opposite leaves. 



1. S. succisA. DeviVs-bit. — Rt. premorse ; stevi Ivs. remotely toothed; hds. 

 ofjls. nearly globose ; cor. in 4 equal segments. — In gardens, though rarely cul- 

 tivated. The stem is about If high. Corolla violet, -f 



2. S. ATROPURPUREA. Moumiiig Bride. — Lvs. pinnatifid and incised ; hds. of 

 Jls. radiant ; receptacle cylindric ; outer crotcn of the seed short, lobed and crenate. — 

 A beautiful species, 2— -4f high, with dense heads of dark purple flowers, f 



Order LXXV. COMPOSITiE.— Asterworts. 



Plants herbaceous or shrubby. 



Lva. alternate or opposite, without stipules, simple though often much divided. 



Fls. collected into a dense head (capitulutn), upon a common receptacle, surrounded by an involucre of 



many bracts (scales). 

 Cat. closely adherent to the ovary, the limo wanting, or membranaceous and divided into bristles, hairs, 



&c., called pappus. 

 Cor. superior, consisting of 5 united petals, either ligulate or tubular. 

 Sta. 5, alternate with the lobes of the corolla. Atit/i. cohering into a cylinder. 



Ova. interior, l-celled, l-ovuled. Style 2-cleft, the inner margins of the branches occupied by the stigmas. 

 FY. an achenia, dry, indehiscent, 1-seeded, crowned with the pappus. 

 This is the most extensive and most natural of all the oroers of the vegetable kingdom, always distin- 



fuished at sight by the capitate flowers and the united anthers. It comprehends 1005 genera (at present 

 nown, 1846), and about 9000 species ; being nearly one-ninth of all the species of flowering plants. The 

 feneral inflorescence is centrifugal, that is, the central o; terminal heads are first developed, while the 

 mflorescence of the heads is centripetal, the outer flowers first expanding. In color the flowers are vari- 

 ous ; sometimes those of the disk and ray are of diflerent colors, again they are all of the same, but in the 

 former case the disk florets are almost always yellow. 



This immense order is difiused throughout all countries of the globe, but in verj' difl^erent proportions. 

 According to Humboldt they constitute about one-seventh of the Phajnogamous Flora of (iermany, one- 

 eighth, of France, one-fifteenth, of Lapland, one-sixth, of North America (north of Mexico), and one-half, 

 of Tropical America. In New Holland they are in the proportion of about one-sixteenth, according to 

 Brown, while in the island of Sicily they are one-half The Liguliflorai are said to be most abundant in 

 cold regions, and the Tubuliflorse in hot regions. The Labiatiflorai are almost exclusively confined to 

 South America. In the northern parts of the world the Composit<e are universally herbaceous, but towards 

 the tropics they gradually become frutescent and even trees. In Chili they are generally shrubs, and on 

 the island of St. Helena they are trees. 



Properties, ^c— The Composita? furnish comparatively few useful- products. A bitter principle per- 

 vades the whole, which, when combined with resin and astringent mucilage, becomes tonic andfebrifu- 

 gal, as in the camomile, colt's-foot, thoroughwort, goldenrod, &c. Some are anthelmintics from the 

 prevalence of the resinous principle, as tansey, Artemisia, Vemonia. Others are aromatic and extremely 

 bitter, as wormwood and all the species of Artemisia. Other species are verj' acrid, as mayweed. Fhe 

 Jerusalem artichoke (Helianthus tuberosus), the vegetable oyster (Tragopogon) , the true artichoke 

 (Cynara), lettuce, dandelion and a few others, are the only species useful for food. The order abounds in 

 ornamental plants of the highest interest to the florist, and of easy culture. Among these are the splen- 

 did DahUas and Chinese Chrysanthema, with the numerous progeny of Aster, Helianthus, Xeranthemum, 

 Coreopsis and multitudes of others, constituting the richest ornaments of the autumnal flower garden. 



The inflorescence of the Compositae is peculiar, and its real nature often complex and obscure. Tlie 

 following definitions /)f terms are given with reference to this order only, and if understood, will remove 

 many dimculties that lie in the student's way m the investigation of this subject. 



CapituIu7tioT head {compound Jlower of the earlier botanists); a collection of flowers (^rete) on a 

 common receptacle (rachis), as in Aster. Helianthus, &c. 



Involucre (calyx by analogy) is the lower and outer envelope of the head. 



Scales ; the modified leaves or bracts composing the involucre. 



Morwphyllous involucre ; where the scales are united by their edges. 

 ■ Pohjphylloits involucre ; where the scales are distinct. 



Simple involucre ; where the scales are equal and arranged in a single row. [short ones. 



Catyculate involucre ; where a single row of scales is surrounded at base by an outer row of very 



Imbricated involucre ; where the scales are in several rows, the outer ones becoming gradually shorter. 



The Receptacle or rachis is the dilated extremity of the peduncle, inclosed by the mvolucre, and upon 

 which the nowers stand. It is 



Colu7}i7iar, flat, conical or depre.ssed,accoT(img to its form; 



Paleaceous or chaffy, where the flowers are subtended by chaffy scales which are analogous to bracts ; 



Alveolate, where it presents the appearance of a honey-comb, each flower having been sunounded by a 

 membranous rim or involucel ; 



Areolate, where the alveoli are reduced to a mere line ; . - 



Pimbrillate, where the alveoli are split into teeth or bristles ; 



Naked, when smoothish, being destitute of chaff, alveoli, bri.stles, &c. 



