456 PROCEEDINGS OF THE AMERICAN ACADEMY. 
It will be noticed that a few species are herein treated which have not 
as yet been reported from Mexico or Central America. In these cases 
the known locality is such that the occurrence of the species may be ex- 
pected in Northern Mexico. Besides the material in the Gray Her- 
barium, the writer, through the kindness of Dr. J. N. Rose, has been 
permitted to borrow from the U.S. National Museum for examination 
the Mexican and Central American specimens of these two genera. 
GALIUM, Linn. (Name from ancient Greek ydAcov, supposed to 
be Galium verum, and derived by Dioscorides from ydAa, milk, which it 
was used to curdle.) _ Flowers perfect, polygamo-dicecious, or unisexual, 
exinvolucrate. Calyx-tube ovoid or globose; limb obsolete. Corolla 
rotate, usually 4-lobed (not unfrequently 3-lobed, and rarely 5-lobed); 
lobes valvate. Stamens of the same number and alternating with the 
lobes of the corolla, adnate to the base of the tube: anthers on short fila- 
ments, exserted. Disk annular. Ovary 2-celled; styles more or less 
2-cleft ; stigmas capitate; ovules solitary in the cells, borne on the dis- 
sepiment, amphitropous. Fruit didymous, dry, subcarneous, or distinctly 
baceate, smooth, tuberculate, or hispid, separating into closed carpels, oF 
only one carpel maturing. Seeds concave on the face; embryo curved ; 
cotyledons foliaceous ; radicle inferior. — Annuals, herbaceous perennials, 
or rarely suffruticose plants. Leaves in whorls of 3 to many. Flowers 
usually disposed in axillary or terminal cymes, occasionally simply 
axillary, or terminal, white, yellow, greenish, or purplish. — Gen. 24; 
Benth. & Hook. f. Gen. ii. 149; Gray, Syn. Fl. N. A. i. pt. 2, 35 (excl 
§ eared in part); Schumann in Engl. & Prantl, Nat. Pflanzent. iv. 
Ab. 4, 149. For generic synonyms, which relate chiefly to the Old 
World, see Hooker f. & Jackson, Index Kewensis, i. pt. 2, 991. 
§ 1. Fruit uncinate-hispid, or granular-papillose. 
* Leaves in whorls of six or eight (rarely of ten or more) ; the angles of the stem 
as well as the midrib and margins of the leaves usually retrorsely aculeolate 
hispid, less frequently smoothish, or rarely (in G. triflorum) somewhat hirsute. 
+ Stems smoothish, or rarely somewhat hirsute-pubescent. 
G. TRIFLoRUM, Michx. Herbaceous: stems more or less pubescent: 
leaves elliptic-lanceolate to narrowly oblong-lanceolate, cuspidate-acum!- 
nate, 1.5 to 4 or rarely 8 em. long, 5 to 10 or rarely 15 mm. broad, 
usually covered on the upper savtics near the margin with subappressed 
idulous hairs, often slightly hispid on the midrib, mah glabrous :_ 
terminal, usually 3-flowered. — Fl. i. 80; illd. 
Hors Berol. t 66; DC. Prodr. iv. 601; Torr. & Gray, Fl. ii. 23; 
