222 COMPOSITE FAMILY. 



68. CTNARA. 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 involucre abruptly tipped with a spreading, slender, 

 awl-shaped appendage, mostly hooked at its point. Receptacle 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, many flower s s 

 and the two 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. 



66. 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. 



6T. 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 

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

 or many bristles or narrow scales, or none. 



+--+- 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 floioers 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. 



63. 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 8-5-toothed corolla. Akenes angled or ribbed, with a flat top, crowned with a 

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



54. 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 of pappus. 

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

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



