Rvdberg : Studies ox the Rocky Mountain flora 23 



The Rocky Mountain specimens agree in this respect with L. 

 virosa. They have also the obtuse lower leaves of that species 

 as figured by Morison, as illustrated in Sweet's English Botany, 

 in Baxter's British Phaenogamous Botany, and in the Flora von 

 Deutschland. Allioni's illustration of L. augustana shows only 

 the upper part of the plant, but all the leaves shown are decidedly 

 acute. 



Lactuca polyphylla sp. nov. 



Biennial; stem stout, about i m. high, glabrous; leaves sessile 

 and slightly auriculate-clasping, very numerous, linear-lanceolate, 

 entire, acuminate, 1-2 dm. long, glabrous, not at all spinulose; 

 panicle conical, much branched, about 3 dm. long, 1.5 dm. broad; 

 involucres about 1 cm. high; outer bracts lanceolate, about half 

 as long as the linear-lanceolate inner ones; achenes nearly black, 

 3-4 mm. long, oval, indistinctly 3-nerved, transversely rugose; 

 beak about 2 mm. long. 



The type was determined as Lactuca integrifolia Bigel., but 

 it differs from that purely eastern species in the numerous more 

 willowlike leaves, the stout stem, the numerous heads in a more 

 compact panicle and the short beak of the achenes. 



Idaho: Lake Pend d'Oreille, Aug. 5, 1885, E. L. Greene (type 

 in herb. Columbia Univeristy). 



New York Botanical Garden. 



Bronx Park, New York City 



