222 CO.MPOSITE FAMILY. 



66. C YNARA. Sc.iles of tlie involucre of the great heads thickened and fleshy towards the 



base, coininonly notched at the end, with or without a prickle. Akenes sHghtly 

 ribbed. Otherwise much as in the last. 



■n- +*■ Pappus of naked, rough, or short-barhed bristles, or none. 



6-1. ARCTIUM. Scales of the gloliular involucre abruptly tipped with a spreading, slender, 

 awl-shaped appendage, mostly hooked at its point. Receptacle bri.stly. Akenes 

 flattened, wrinkled ; pappus of many short and rough bristles, their ba.scs not 

 united, deciduous. Leaves and stjilks not prickly. 



68. CAKTH.VMUS. Outer scales of the involucre leaf-like and spreading, niiddlo ones with 

 ovate api)endage 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 ->-- +- 



+- +- Tkistle-Hlce, with m<tny-ranked imbricated scales to the involucre, maiiy floicers, 

 and the two branches of the sti/le united into one body almost or quite to the tip. 

 as in -i- ,■ but the outer floicers of the head different from the rest and sterile 

 except in a few kinds of Centaurea. Jieceptacle beset iviih 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-cj'lindrical, 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 man}' bristles or narrow scales, or none. 



^- -!- -H Bur-like or achenium-like in the fruit, which is a completely closed involucre 

 containing only one or tico flov:ers, 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 inrolucre. 

 Heads therefore moitwcious, or rarely diwcious ; no paj)pus. Coarse and 

 homely weeds. 



32. AMBROSLV. 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 starainate, 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; fertfle flowers below them, clustered in the axils, two 

 together in a 2-celled hooked prickly bur. 



-)- -i- -(- -f- Plants not thistle-like, spiny, nor bur-like in their fruits, heads, or herbage. 



*+ Two kinds of flowers in the same head, the outer ones with ])ist its only. 



™ Pappus none, or a minute border or cup. 



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

 imbricated. Bitter-aromatic or rather acrid plants. 



53. TAN.\CETUM. Heads of many yeflow flowers; the marginal ones with pistil only 



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

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



54. ARTEMISIA. Heads small, of few or m.any yellow or dull purplish flowers, some of 



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

 ing tlie ovary. Akenes obovate or club-shaped, smaU at the top, destitute of pajipus. 

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

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



