64 COMPOSITE. CffiLESTINA. 



Subtribe 1. Eupatorie^, DC. — Heads discoid ; the flowers all perfect 

 and similar, usually white, rose-color, or purple (rarely ochroleucous), 

 never yellow. 



Div. 1. Agerate^, Less. — Pappus composed of chaSy often unequal 



scales, sometimes aristate or coroniform. 



7. CCELESTINA. Cass. diet. 6. svppl. p. 8, <^-26. p. 221 ; Less. syn. p. 

 155 ; DC. prodr. 5. p. 107. 



Heads many-flowered. Involucre cylindrical-hemispherical ; the scales 

 numerous, narrow, somewhat imbricated. Receptacle convex, chaffy or 

 naked. Achenia glabrous, 5-angled. Pappus coroniform or cup-like, slight-. 

 ly toothed, or sometimes produced into one or two longer teeth or chaffy 

 scales. — Annual (tropical American) branching herbs, with terete stems, and 

 opposite petioled and toothed leaves. Heads in rather dense corymbs, pedi- 

 cellate. Flowers blue or purple. 



§. Receptacle naked. — Ageratoides, DC. 



1 . C. maritima : stem decumbent, branching, nearly glabrous ; leares 

 smooth and glabrous, slightly fleshy, ovate or oval, serrate, tapering into a 

 slender petiole ; tube of the corolla sparsely pubescent with jointed hairs ; 

 pappus minute and coroniform, often with one or two slightly produced teeth, 

 sometimes obsolete. 



Key West, Florida, Mr. Bennett! Mr. Blodgett! — Leaves scarcely an 

 inch long. Flowers blue. — We have seen specimens of a very similar plant 

 from Cuba; which however has a pappus of 5 distinct mostly aristate chaffy 

 scales, and is therefore an Ageratum : it agrees with the description of Kanth's 

 A. ? maritimiim, (from the same locality) as to the foliage, (kc, but not as to 

 the corolla and pappus. — Surely Coslestina (at least the section Ageratoides) 

 and Ageratum are not sufficiently distinct. 



8. AGEPvATUM. Linn. ; Gcertn.fr. t. 165 ; DC. prodr. 5. p. 108. 



Heads many-flowered, subglobose. Scales of the involucre numerous, 

 imbricated, linear, acuminate. Receptacle naked. Corolla tubular, dilated 

 above, 5-lobed. Branches of the style exserted, cylindraceous, rather obtuse. 

 Achenia 5-angled, narrowed at the base, with a rather large callus. Pappus 

 of 5-10 distinct chaffy scales, either aristate-acuminate, or obtuse and pecti- 

 nate. — Mostly annual (tropical) herbs, with opposite petioled and toothed 

 leaves, and corymbose heads. Flowers blue or white. 



1. A. conyzoides (Linn.) : stem branching; leaves ovate, rhomboid, or 

 cordate, on rather long petioles ; pappus of 5 somewhat serrate chaffy scales, 

 dilated at the base, acuminate-aristate ; the subulate awns as long as the 

 corolla (flowers blue or white). — Linn. spec. 2. p. 839 ; Sicartz, obs. p. 301 ; 

 Schkuhr, handb. t. 238 ; Hook. exot. fl. t. 15 ; DC. prodr. b.p. 108. 



Wet places near Savannah, Georgia, Mr. Curtis I April-June. — Found 

 in almost every country within or near the tropics, varying greatly in the 

 form of the leaves ; the stem and petioles also sometimes hispid, but occasion- 



