310 LXXV. COMPOSITE. 



tivated for the use of the clothiers (fullonum}, who employ the 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 ; plants 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 setae, 

 sometimes partially abortive. % Large, mostly European herbs with 

 opposite leaves. 



1. S. sucdsA. Devil' s-bit. Rt. premorse ; stem Ivs. remotely toothed ; Ms. 

 offls. 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. Mourning Bride. Dos. pinnatifid and incised ; hds. of 

 fls. radiant ; receptacle cylindric ; outer crown of the seed short, lobed and crenate. 

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



ORDER LXXV. COMPOSITE ASTERWORTS. 



Plants herbaceous or shrubby. 



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



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



many bracts (scales). 

 Cal. closely adherent to the ovary, the limn 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. Anth. cohering into a cylinder. 



Ova. inferior, 1-celled, 1-ovuled. Style 2-cleft, the inner margins of the branches occupied by the stigmaa. 

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



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

 guished at sight by the capitate ftowers and the united anthers. It comprehends 1005 genera (at present 

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

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

 inflorescence 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 different colors, again they are all of^the same, but in the 

 former case the disk florets are almost always yellow. 



This immense order is diffused throughout all countries of the globe, but in very different proportions. 

 According to HumboldL they constitute about one-seventh of the Phtenogamous Flora of Germany, one- 

 eighth, ot'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 pne-half The Liguliflora; are said to be most abundant in 

 cold regions, and the Tubuliflorae in hot regions. The Labiatiflora? are almost exclusively confined to 

 South America. In the northern parts of the world the Composite 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 Composite? furnish comparatively few useful products. A bitter principle per- 

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

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

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

 bitter, as wormwood and all the species of Artemisia. Other species are very acrid, as mayweed. The 

 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 Dahlias 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 Composite is peculiar, and its real nature often complex and obscure. The 

 following definitions jof terms are given with reference to this prder only, and if understood, will remove 

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



Capitulum or head (compound flmoer of the earlier botanists) ; a collection of flowers (florets) 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. 



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



Polyphyllous involucre ; where the scales are distinct. 



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



Calyculate 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 involucre, and upon 

 which the flowers stand. It is 



Columnar, flat, conical or depressed, according to its form ; 



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



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

 membranous rim or involucel ; 



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



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



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



