130 



SHORTER NOTES. 



y An Undescribed Opuntia from Jamaica. — Opuntia jamai- 

 censis Britton & Harris sp. nov. Erect, dull green, i m. high or 

 less, subcylindric below, the several branches ascending, Joints 

 obovate, much narrowed at the base, flat, rather thin, readily 

 detached, 7-13 cm. long, 5-7.5 cm. wide; areoles about 2.5 cm. 

 apart, those of the lower parts of the joints usually without 

 bristles, the others bearing 1-5 (usually 2) acicular, unequal white 

 spines 2.5 cm. long or less, with yellowish-green tips, the numerous 

 glochides fulvous; flowers about 4 cm. broad, opening at ii 

 o'clock A.M. and beginning to close at 4 p.m.; sepals small, green, 

 scale-like; petals 16-18, in about 3 series, those of the two outer 

 series yellowish-green, triangular, 1.2 cm. long or less, apiculate; 

 those of the inner series 6, light lemon-yellow with a reddish- 

 brown streak at the middle, obovate-orbicular, 2.5 cm. long; 

 filaments greenish-white; anthers white ; style white, longer than 

 the stamens; stigmas 7 or 8, creamy-white; fruit pyriform, con- 

 cave at top, red, much narrowed at the base, 3.5-4 cm. long, 

 2-2.2 cm. thick, its areoles about i cm. apart, bearing many 

 yellow-brown glochides ; seeds densely persistently woolly, 

 biconvex, brown, 4 mm. broad, 1.5 mm. thick, the raphe promi- 

 nent. 



Roadside plains near Salt Ponds, St. Catharine, Jamaica, 

 Britton &■ Harris, 10,881, August 31, 1908 (type); same locality 

 {Britton 3o6g) ; flowered at Hope Gardens, Jamaica, January, 

 19 10, and fruited in April, 19 10. 



I tentatively refer the species to the series Divaricatae Salm- 

 Dyck, from all of which it differs, however, in its erect habit and 

 subcylindric trunk. 



N. L. Britton. 



New York Botanical Garden. 



Some Records from the Potomac District. — The following 

 collections made in the vicinity of Washington, D. C, during 

 the summer of 1910, have seemed worthy of record. 



Eleocharis flaccida (Spreng.) Urban, determined by Dr. N. L. 

 Britton [= £. ochreata (Nees) Steud, of our manuals] collected 

 at the mouth of Cameron Run, near New Alexandria, Fairfax 

 Co., Va., Aug. 13, 1910, Philip Dowell 6454, Pennell 2^8g. 



