15 
AGERATUM conyzoides. 
Hairy Ageratum. 
SYNGENESIA POLYGAMIA ^QUALIS Nat. Ord. COMPOSITjE, De Cand. 
SYNANTHEREM, Trib. EoPATORiat, Cass. 
Gen. Char. — Recepfaculum nudum. Pappus paleis 5, subaristatis. Involu- 
crum oblongum, duplici foliorum serie. Corollnlce 4 seu 5-fidae, Willd. 
Ageratum conyzoides; foliis ovato-rhomboideis, caule piloso, paleis pappi 
aristatis denticulatis. 
A. conyzoides, Willd. Sp. PL v. iii. p. 1773. — Ait. Hort. Kerv. ed 2. v. iv. 
p. 509 — ScHKUHR, Boi. Handb. t. 238. 
Stem, 1-2 feet high, cylindrical, hairy, erect, much branched, with the 
branches opposite, erecto-patent. Leaves ovate, approaching to rhom- 
boid, rugose, recurvo-patent, pubescent, the lower part of the margins 
acutely serrated, petiolated ; petioles as long as the leaf, grooved, pilose. 
Flowers bright blue, inclining to purple, in terminal and lateral small pe- 
dunculated corymbs, which have small bracteas at the base of the stalk. 
Involucre ovato- cylindrical, slightly pilose, composed of about 14 erect 
scales in 2 rows, of which the outer half are oblongo-lanceolate, the inner 
(alternate with the outer) almost setaceous ; they appear slightly toothed, 
under a high magnifying power. Receptacle small, naked, containing few 
florets, which are shorter than the involucre, so that nothing but the 
styles are protruded. Corollules tubular, with 5 blue teeth, the rest white. 
Styles much protruded, filiform, pubescent, blue. Germen scabrous, ter- 
minated by 5 white setae, which are broad at the base. Pericarp (achenium) 
blackish-brown, soon falling out from the expanded involucre. Pappus 
of 5 ovate scales, terminated each by a long arista, minutely toothed for 
their whole length. 
A native of South America and the West Indian Islands, 
and an annual, but easily propagated, and well deserving of a 
place in every stove. It flowers during a considerable period of 
the summer ; and even the severities of winter witness the ex- 
pansion of its pretty blue blossoms. 
VOL. I. 
