VOL. XI, PP. 169-171 JUNE 9, 1897 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



TWO NEW PLANTS FROM MOUNT MAZAMA, OREGON. 

 BY FREDERICK V. COVILLE AND JOHN B. LEIBERG. 



Arenaria pumicola, sp. nov.* 



Plant forming a rather loose tuft, commonly 6 to 12 cm. high, from a 

 caudex with a deep tap-root and with naked ascending branches com 

 monly 1 to 2 mm. in thickness ; stem erect, smooth below, glandular-hairy 

 above, with commonly 1 to 3 pairs of cauline leaves; basal leaves numer 

 ous, about 0.5 to 0.7 mm. wide by 10 to 20 or even 30 rum. long, glabrous, 

 glaucous, entire to remotely or sometimes even closely denticulate on the 

 margin, abruptly and rather bluntly acute at the apex, the cauline leaves 

 similar but about twice as broad and seldom more than 10 or 12 mm. 

 long; inflorescence at the first flowering compact, in age open, the 

 branches of the cyme and often the midribs of the sepals glandular- 

 hairy ; bracts ovate, acute to acuminate, scarious, glabrous ; sepals 2 to 3 

 or sometimes even 4 mm. long, ovate, with a sharply defined midrib and 

 broad scarious margins, acute or through the expansion of the margins 

 obtuse; petals about twice as long as the sepals, cuneate-oblanceolate, 

 emarginate or erose at the usually truncate apex ; stamens about as long 

 as the petals, the anthers commonly purple ; ovary globose ; capsules at 

 maturity probably nearly twice as long as the calyx ; mature seeds not 

 seen. 



Type specimen in the United States National Herbarium, collected 

 August 13, 1896, at Crater Lake, Oregon, at an altitude of 2180 meters, by 

 Frederick V. Coville and John B. Leiberg, No. 349. 



This plant appears to be most closely related to Arenaria 

 aculeata Wats., differing in the naked, ascending, subterranean 

 caudex branches bearing the congested foliage in tufts at their 



* On the ground of euphony the combination of letters icic, which in 

 strict etymological practice would occur in this word, has been reduced 

 to ic. 



39-Bior,. See. WASH., VOL. XI, 1897 (169) 



