EupatoriaceaJ] composite. 171 



below the branches, which are elongated, obtuse, and usually thicker or dilated 

 upwards. 



5. ADENOSTEMMA, Forst. 



Flower-heads, florets, and style of JEupatorium. Achenes obovate-oblong, 

 contracted at the base. Pappus of 3, 4, or 5 short stiff spreading bristles, 

 each tipped by a globular or club-shaped gland. 



A genus of a very few American species, one of which spreads all round the warmer zone 

 of the globe. 



1. A. viscosum, Forst. ; DC. Prod. v. 111. Stem annual, erect or as- 

 cending, rooting at the base, and possibly renewed a second year by a creep- 

 ing rootstock or by stolones, glabrous or glandular-pubescent, 1 to 2 feet high. 

 Leaves few, opposite, stalked, from ovate to broadly triangular, usually coarsely 

 toothed, from barely an inch long and rather thick and rough, to 3 or 4 in. 

 long, thin and glabrous. Flower-heads hemispherical, 3 to 4 lines diameter, 

 in a loose, spreading terminal 2- or 3-chotomous panicle, with very small leaves 

 under the branches. Involucral bracts oblong, in about 2 rows. Florets 

 numerous, often hairy outside. Achenes more or less muricate or rarely quite 

 smooth. 



Little Hongkong, Wilford. A common weed in the warmer regions of the globe, espe- 

 cially in the Old World, where it extends northwards to Japan and southwards to North 

 Australia. The species should include all those published by De Candolle and others from 

 the Old World, and at least the A. brasiliense and A . triangulare among the American ones. 



6. AGERATUM, Linn. 



Flower-heads, florets, and style oiEwpatoriwm. Achenes angular. Pappus 

 of 5 or 10 chaffy scales or bristles dilated at the base. 



A genus of a small number of American species, one of which is spread all over the 

 warmer regions of the globe. 



1. A. conyzoides, Linn.; DC. Trod. v. 108 ; Hook. Ex. Flor. t. 15. 

 An erect branching annual, 1 to 2 feet high, more or less hirsute with spread- 

 ing hairs. Leaves opposite, stalked, ovate, crenate. Flower-heads rather 

 small, in dense terminal cymes. Involucral bracts striate, pointed, in about 2 

 rows. Florets numerous, pale blue or white. Achenes black, smooth. Pappus 

 of 5 lanceolate aristate chaffy scales, often serrate in the lower part. 



Waste places, Hance, Seemann, Wright. A common weed, all over the warmer regions of 

 the globe. 



7. EUPATORIUM, Linn. 



Flower-heads cylindrical, campanulate or hemispherical, with several or many 

 florets. Involucral bracts imbricated, in 2 or more series. Receptacle flat or 

 slightly convex, naked. Corolla tubular, with a campanulate 5-toothed limb. 

 Branches of the style elongated, obtuse. Achenes 5 -angled, without inter- 

 mediate striae. Pappus of a single series of slender, capillary bristles. — Peren- 

 nial herbs or shrubs, or more rarely annuals. Leaves opposite or very rarely 

 alternate. Heads mostly corymbose. Green parts of the plant often sprinkled 

 with resinous glands. 



