COMPOSITE. 321 



Order LV. COMPOSIT^E. Vaill. ; Linn. The Composite Tribe. 



Flowers collected into a dense head (compound flower of the older botanists), ou 

 a common receptacle, and surrounded by bracts (scales) forming an involucre 

 common calyx of LinncsusJ ; the separate flowers often furnished with brac- 

 teoles (chaff or palese). Tube of the calyx coherent with the ovary, and 

 inseparable from it ; the limb (called pappus) composed of bristles, plumose 

 hairs, scales, etc., or rarely foliaceous, often wanting or reduced to a mere 

 margin. Corolla usually composed of 5 united petals, either ligulate or tubular. 

 Stamens 5 (rarely fewer) ; the anthers hnear, united into a tube (syngenesious), 

 sometimes with an appendage at the top (appendiculate), or at the base (caudate). 

 Ovary one-celled, with a single erect ovule : style in the fertile flowers 2-cleft ; 

 the lobes or branches mostly flattish inside, and often furnished with hairs for 

 collecting the pollen, the proper stigmatic surface being in the form of slightly 

 elevated lines along the inner margin.* Fruit an achenium, 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 ; the branches 

 often corymbose. Flowers in each head expanding from the margin to the 

 centre ; either all of the same color (homochromous), or the marginal ones 

 different from those of the disk (heterochromous'). 



An immensely large and very natural order, embracing about one-tenth of all the phencgamous plants of the world, or 

 of this State about one-ninth. The head of flowers may be considered as a very short or contracted spike ; the receptacle 

 being the axis, and the scales of the involucre and the chaff, the bracts. The head is said to be homogamovs, when ail 

 the flowers are perfect ; or helerogamous, when the mnrginal ones are pistillate or neuter, and the others are perfect or 

 staminate. It is discoid, when all the flowers are tubular ; ligulate, when they are all flat or ligulate ; and radiate, when 

 the marginal ones only are ligulate, and the others tubular. Sometimes the flowers are wholly staminate on one plant 

 and pistillate on another, when they are said to be dicecicnis. The receptacle is paJeaccons or chaffy, when it is covered 

 with membranaceous scales (generally thinner than those of the involucre, and like them consisting of modified bracts^: 

 it is naked, when destitute of scales; alveolate, when, after the achenia are removed, it is deeply pitted hke a honeycomb; 

 fmbriUale, when the margins of the little cells are fringed or bristly ; areolate, when divided into numerous little angular 

 spaces. 



* As the characters of the tribes are chiefly taken from the forms of the style and the stigmatic surfaces, these must be 

 carefully studied, and the student must become familiar with their various appearances. 



[Flora.] 41 



