94 



Puidiam occidentale. — P. testa P. variabilis (Prime) affinis ; 

 rotundato-ovata, obliqua, inequilatera, hyalina vel fusco-cornea ; 

 natibus approxirnatis vix prominentibus ; striae minutissimoe. 



Long. 4 mill. 

 Alt. 3^ " 



Hab. " Ocean House," San Francisco. 



Shell near P. variahile (Prfme) roundly ovate, oblique, inequilat- 

 eral, transparent or brown horn color ; umbones approximate but 

 slightly prominent ; striae extremely minute. 



We are indebted for the discovery of this, and many other 

 species, to the researches of the Rev. Mr. Rowell, of San Fran- 

 cisco. 



This is the first species of the genus Pisidium found in our 

 country west of the Rocky mountains. 



February ISth, 1861. 

 President in the Chair. 



Dr. Kellogg presented the annexed description : 



Pibes balsamifera (Kellogg). Fig. 25. Glandular ly villous and 

 viscid or resinous throughout ; stem and older branches smooth ; 

 shining mottled greyish and cherry colored bark. 



Leaves pHcate in vernation, sub-reniform-cordate, slightly three 

 to eight-lobed, incisely many toothed, lamina thin, pale glaucous 

 hue ; translucent nerves numerous, radiating. 



Flowers bright yellow (from the same buds as the leaves) about 

 five, in a condensed raceme (rachis rarely one-half an inch long) 

 nodding, (?) tubular calyx long, slender below, slightly inflated and 

 expanding above, segment of the border very short, ovate acute, 

 apex apiculate, recurved, villous externally. 



Petals minute, entire, (rarely a little crenate) broadly obovate 

 on a slender cuneate claw ; stamens included, filaments shorter than 

 the glabrous anthers ; pistil exsert, glandularly villous, stigma doubly 

 capitate. 



Bracts foliaceous, obovate, nerved, cut dentate at the broad some- 

 what truncate summit, entire at the base, about five or six times 

 the length of the very short pedicels, a subulate bractiole opposite 

 at the base. 



Fruit (in the half-grown state) round ten-nerved, viscid villous. 



This plant was brought to us by Dr. J. A. Veatch from Washoe. 

 We are aware that the habitat causes much variation in the genus 

 Ribes ; but this appears to be quite distinct. The plant exhales 

 the refreshing odor of Populus balsamifera, hence the specific 

 name. 



