Vol. 31, pp. 189-196 December 30, 1918 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



SOME WESTERN SPECIES OF LATHYRUS. 



BY C. V. PIPER. 



In connection with economic investigations of species of 

 Lathyrus it has been necessary to study some western species 

 critically. Several of these species show wide variation in the 

 characters of the leaflets, stipules and also of the tendrils, 

 so that such differences do not justify the valuation which 

 some botanists have placed upon them. Pubescence when 

 present seems on the other hand to be a fairly stable charac- 

 teristic, but now and then specimens occur which apparently 

 are glabrous forms of species usually pubescent. 



Lathyrus ochropetalus, n. sp. 



Perennial, wholly glabrous, slightly glaucous; stems slender, angled 

 or very narrowly winged, 1-1.5 m. high; leaves with 3 to 10 mostly 8 

 leaflets and well developed tendrils; leaflets scattered, membranaceous, 

 not flaccid, ovate-lanceolate, acute, cuspidate, green above, pale beneath, 

 shortly petiolulate, 3-5 cm. long; stipules large, ovate, subentire; peduncles 

 shorter than the leaves; racemes mostly 7-13 flowered; pedicels as long as 

 the calyx-tube; calyx wholly glabrous, the tube 5 mm. long, the two upper 

 teeth short and broadly triangular, the lateral ones oblong-lanceolate, 

 acute, as long as the tube, the ventral lobe longer and narrower; corolla 

 15 mm. long, pale ochroleucous but drying darker; pods linear, nearly 

 straight, 3 cm. long, pendent; seeds globose, bright brown, the linear 

 hilum nearly as long as the diameter. 



Specimens examined : 

 Washington: Seattle, Piper No. 482 (type sheet 218,905 in U. S. 



National Herbarium); Olympia, Henderson No. 2348. 

 Oregon: Roseburg, Cusick No. 4159; Myrtle Point, Holzinger June 



5, 1893; Antelope Creek, Jackson County, Applegate 

 No. 2361. 



This species occurs in open woodlands often with L. polyphyllus Nutt. 

 It has been referred to both L. sulphureus Brewer and L. ochroleucus 



45— Proc. Biol. Soc. Wash.. Vol. 31, 1918. (189) 



