134 BOTANY. 



partite, with bracts at the base. Corolla inserted at the base of the calyx, 

 monopetalous, nearly regular, withering ; limb five-parted, having central 

 veins in its segments, which divide at the top into two recurrent marginal 

 veins ; aestivation valvate. Stamens five, inserted with, but free from, the 

 corolla, alternating with its segments ; anthers articulated with the short 

 filaments, dithecal, introrse, dehiscing longitudinally. Ovary free, unilocular ; 

 ovule solitary, erect, anatropal ; style single ; stigma inclosed in a two- 

 valved cup or indusium. Fruit a utricle, inclosed in the hardened calycine 

 tube. Seed solitary, erect, exalbuminous ; embryo straight ; cotyledons 

 fleshy ; plano-convex ; radicle minute, inferior. Stemless herbaceous plants, 

 with radical, exstipulate leaves, and capitate flowers, supported on scapes, 

 and surrounded by an involucre of enlarged bracts. Natives of New 

 Holland. Their properties are unknown. The order contains as yet only 

 one genus and nine species. Example : Brunonia. 



Order IIG. Comtosit^e, Syngenesia of Linn. Flowers collected into a 

 dense head (compound flowers of the older authors) upon a common 

 receptacle, surrounded by an involucre. Tube of the calyx coherent with 

 the ovary, and undistinguishable from it ; the limb (called pappus) composed 

 of bristles, or scales, &c., or very rarely foliaceous, often wanting or reduced 

 to a margin. Corolla composed of mostly five united petals ; either ligulate 

 or tubular, in the latter case with a valvate aestivation ; the tube generally 

 furnished with five nerves (or more properly ten united in pairs), which 

 extend from the base to the sinuses, where they divide, a branch coursing 

 along or near each margin to the apex of the lobes. Stamens as many as 

 the lobes of the corolla and alternate with them : the filaments (distinct or 

 united above) inserted into the tube ; anthers linear, coherent by their 

 margins into a cylinder {syngenesious). Ovary one-celled, containing a 

 single erect anatropous ovule ; style (usually undivided in the sterile 

 flowers) two-cleft ; the lobes or branches (incorrectly called stigmas) various 

 in form, mostly flattish within, often furnished with collecting hairs ; the 

 proper stigmas occupying their inner margins, in the form of glandular, 

 slightly prominent lines. Fruit an indehiscent, dry, one-seeded pericarp 

 (achaenium), crowned with the limb of the calyx or pappus. Seed destitute 

 of albumen. Radicle short ; cotyledons flat or plano-convex. Herbs, 

 rarely shrubs or trees (forming about one tenth of phanerogamous vegetation) ; 

 with alternate or opposite, sometimes divided or lobed, exstipulate leaves. 

 Branches often corymbose, terminated by the heads, the central ones earliest 

 developed. Flowers in each head expanding successively from the margin 

 (or lower portion) to the centre or apex, either all of the same color 

 (homochromous), or the marginal ones different from those of the disk 

 {Jieterochromous), the latter in this case almost always yellow ; either 

 perfect, polygamous, or diclinous. 



This order is both one of the largest and one of the most natural in the 

 vegetable kingdom. The plants are generally distributed over the surface 

 of the globe, and all of the tribes have North American representatives. 

 Generally herbaceous in northern regions, they become at times shrubby 

 and even arborescent in warm climates. The number of known genera 

 134 



