468 PROCEEDINGS OF THE AMERICAN ACADEMY. 



the habit, flowers, and foliage of Galium, but with the leaves in whorls of 

 four, axillary inflorescence, iuvolucrate flowers, and usually fleshy fruit. — 

 Gen. PI. 523 (as a section under Galium) ; Benth. & Hook. f. Gen. ii. 

 149; Schumann in Fl. Bras. vi. pt. 6, 103; Engl. & Prantl, Nat. 

 Pflanzeuf. iv. Ab. 4, 154. Galium § Eelbunium, Gray, Syn. Fl. N. A. 

 i. pt. 2, 40, in part. 



§ 1. Involucre of two bracts : fruit pedicellate. 



1. R. sphagnophilum. A slender delicate annual, pale green, 

 glabrous throughout : stems reclining, rooting at the nodes ; interuodes 

 2 to 12 mm. in length : leaves ovate-elliptic, 2 mm. long, one half to 

 two thirds as broad, acute, narrowed below into a subpetiolate base : 

 peduncles axillary, solitary, 2-bracteate above ; bracts minute, less than 

 1 mm. in length : corolla not seen : fruit baccate, glabrous, about 1 mm. 

 in breadth. — Collected by C. G. Pringle in sphagnum on the Sierra de 

 Clavelliuas, Oaxaca, altitude 2770 m., 17 October, 1894, no. 5812. 

 Probably a near relative of the South American R. humile, Schumann. 



§ 2. Involucre of four bracts : fruit sessile or nearly so. 

 * Leaves elliptic to obovate : plant liirsute-pubescent. 



2. R. hypocarpium, IIemsl. Annual: stems 1 to 10 dm. long, 

 pilose : leaves membranous, 5 to 15 mm. long, 3 to 8 mm. broad, rounded 

 and usually obtusely mucronate at the apex, entire, ciliate, slightly 

 narrowed at the base, pubescent upon either surface, dark green above, 

 paler beneath: peduncles 5 to 15 mm. long: bracts of the foliaceous in- 

 volucre ovate, acute or obtusish, narrowed into a subpetiolate base : 

 flowers sessile ; lobes of the corolla ovate, acutish, ciliate : fruit black or 

 reddish, hirsute. — Biol. Cent.-Am. Bot. ii. 63. R. hypocarpum, Schum. 

 Fl. Bras. vi. pt. 6, 112, t. 92. Rubia hypocarpia, DC. Prodr. iv. 591 ; 

 Valantia hypocurpia, L. Syst. Nat. ed. 10, 1307. V. hypocarpa, L. 

 Spec. ed. 2, ii. 1491. — Jalapa, C. L. Smith, no. 1570; Mirador, Lieh- 

 mann, no. 225; Orizaba, Miiller^ nos. 1551, 1699, Sumichrast, no. 468; 

 Oaxaca, Pringle, no. 5629 ; Guatemala, von Tiirckhcim (no. 721 of 

 Donnell Smith's sets). 



* * Leaves ovate-oblong to oblong-lanceolate: plant glabrous. 



3. R. Isevigatnm, Hemsl. Stems cespitose, diflTusely branched : 

 leaves ovate-oblong or ovate-lanceolate: peduncles axillary: flowers 

 sessile and solitary in the involucre: fruit glabrous. — Biol. Cent.-Am. 

 Bot. ii. 63. Rubia. Icevigata, DC. Prodr. iv. 591 (whence above descrip- 

 tion). Galium leevigatiim, Bartl. in DC. Prodr. iv. 591. — Collected in 

 Mexico by Hcenke. Specimens not seen. 



