222 COMPOSITE FAMILY. 



66. CYNARA. Scales of the involucre of the great heads thickened and fleshy towards the 



base, commonly notched at the end, with or without a prickle. Akenes slightly 

 ribbed. Otherwise much as in the last. 



H- -H- Pappus of naked, rough, or short-barbed bristles, or none. 



64. ARCTIUM. Scales of the globular iuvolucre abruptly tipped with a spreading, slender, 



awl-shaped appendage, mostly hooked at its point. Eeceptacle bristly. Akenes 

 flattened, wrinkled ; pappus of many short and rough bristles, their bases not 

 united, deciduous. Leaves and stalks not prickly. 



68. CARTHAMUS. Outer scales of the involucre leaf-like and spreading, middle ones with 

 ovate appendage fringed with spiny teeth or little spines, innermost entire and 

 sharp-pointed. Receptacle beset with linear chaff. Akenes very smooth, 4-ribbed ; 

 pappus none. Leaves with rigid or short spiny teeth. 



(67) CENTAUREA ; see -- +- 



+- +- Thistle-like, with many-ranked imbricated scales to the involucre, manyflowe^ 

 and the tioo branches of the style united into one body almost or quite to the tip, 

 as in +- ; but the outer flowers of the head different from the rest and sterile 

 except in a few kinds of Centaurea. Receptacle beset with bristles. 



65. CNICUS. Outer flowers smaller than the rest, slender-tubular, sterile. Scales of the 



involucre tipped with a long, spine-like appendage which is spiny-fringed down the 

 sides. Akenes short-cylindrical, many-ribbed, and grooved, crowned with 10 short 

 and horny teeth, within which is a pappus of 10 long and rigid and 10 short naked 

 bristles. Leaves prickly-toothed. 



67. CENTAUREA. Outer flowers sterile and with corolla larger than the rest, often fun- 



nel-shaped and with long, sometimes irregular lobes, forming a kind of false ray ; 

 but these are wanting in a few species. Involucre various, but the scales commonly 

 [with fringed, sometimes with spiny tips. Akenes flat or flattish ; pappus of several 

 or many bristles or narrow scales, or none. 



4- +-+- Bur-like or achenium-like in the fruit, which is a completely closed involucre 

 containing only one or two flowers, consisting of a pistil only, with barely a 

 rudiment of corolla, therefore very different from most plants of the family ; 

 but the staminate flowers are several and in a flat or top-shaped involucre. 

 Heads therefore monoecious, or rarely dioecious; no pappus. Coarse and 

 homely weeds. 



82. AMBROSIA. Heads of staminate flowers in racemes or spikes terminating the stems 



or branches, their involucre of several scales united in a flattish or top-shaped cup ; 

 fertile flowers clustered below the staminate, only one inclosed in each small ache- 

 nium-like involucre, which is naked, or with a few tubercles or strong points near 

 the top in a single row. 



83. XANTHIUM. Heads of staminate flowers in short racemes or spikes, their involucre 



of several scales in one row ; fertile flowers below them, clustered in the axils, two 

 together in a 2-celled hooked prickly bur. 



+- +- +- +- Plants not thistle-like, spiny, nor bur-like in their fruits, heads, or herbage. 



H- Two kinds of flowers in the same head, the outer ones with pistils only. 



= Pappus none, or a minute border or cup. 



I No chaff among the flowers; scales of the involucre dry, often with scarious margins, 

 imbricated. Bitter -aromatic or rather acrid plants. 



53. TANACETUM. Heads of many yellow flowers ; the marginal ones with pistil only 

 and a 3-5-toothed corolla. Akenes angled or ribbed, with a flat top, crowned with a 

 cup-h'ke, toothed or lobed pappus. Very strong-scented herbs, with heads in a corymb. 



64. ARTEMISIA. Heads small, of few or many yellow or dull purplish flowers, some of 

 the marginal ones pistillate and fertile, the others perfect, but sometimes not matur- 

 ing the ovary. Akenes obovate or club-shaped, small at the top, destitute ofpappui, 

 Bitter-aromatic and strong- seen ted plants, with heads in panicles. 



(52) CHRYSANTHEMUM. One species, of old yards, is discoid (p. 226). 



