VOL. II.] 



PEA FAMILY. 



331 



4. Lathyrus myrtifolius Muhl. Myrtle-leaved Marsh Pea. (Fig. 2218.) 



Lathyrus myrtifolius Muhl.; Willd. Sp. PI. 3: 



1091. 1803. 

 Lathyrus palustris var. myrtifolius A. Gray, 



Man. Ed. 2, 104. 1856. 



Perennial, usually quite glabrous; stems 

 slender, angled, not winged, i-3 long, 

 weak. Stipules obliquely ovate, or half- 

 sagittate, 6 // -i2 // long, often 4 // -6 // wide 

 and toothed; leaflets 2-4 pairs, mostly 3 pairs, 

 oval, oval-oblong or ovate, mucronate and 

 acute or obtuse at the apex, narrowed at the 

 base, 9 // -2 / long, 3 // -7 // wide, rather thin; 

 tendrils branched; peduncles equalling the 

 leaves, or shorter, 3-9-flowered; flowers pur- 

 ple or purplish, similar to those of the pre- 

 ceding species; pod linear, glabrous, sessile, 

 i'-2 x long, 3J4" wide or less. 



In moist or wet grounds, Neyv Brunswick to 

 Manitoba, south to North Carolina and Tennes- 

 see. May-July. 



Lathyrus myrtifolius macranthus White, Bull. 

 Torr. Club, 21:448. 1894. 



Pubescent; stipules larger, often half as large 

 as the leaflets; flowers 10-12" long. Maine. 



5. Lathyrus decaphyllus Pursh. 

 Prairie Vetchling. (Fig. 2219.) 



L. decaphyllus Pursh, Fl. Am. Sept. 471. 1814. 

 Lalhyruspolymorphus Nutt. Gen. 2: 96. 1818. 



Perennial, erect or ascending, glabrous, 

 or finely pubescent, 6 x -i8' high. Stems 

 angled; stipules half-sagittate, acuminate, 

 4 // -i2 // long, i // -3 // wide; leaves petioled; 

 leaflets 3-7 pairs, obtuse or acute and 

 mucronulate at the apex, narrowed at the 

 base, thick, conspicuously reticulated, i / - 

 2>' long, 3 // -S' / wide; stipules when 

 present, branched, but often wanting; 

 peduncles usually shorter than the leaves; 

 flowers purple, i'-i% f long, showy; pod 

 linear, stipitate; seeds with a narrow stalk 

 and short hilum. 



Kansas (?), Idaho and Colorado to Arizona 

 and New Mexico. March-July. 



6. Lathyrus ornatus Xutt. Showy 

 Vetchling. (Fig. 2220.) 



Lathyrus ornaius Xutt. ; T. & G. Fl. N. A. I : 

 277- 1838. 



Closely resembling the preceding species, 

 but generally lower, often less than i high. 

 Stipules lanceolate or linear, 2 // -io // long; 

 leaflets narrow, linear or linear-oblong, acute 

 and mucronate, 4 // -i2 // long, i // -2 // wide; 

 tendrils commonly wanting; flowers purple, 

 showy, i'-iyt f long; pod linear, stipitate; 

 seeds with a broad stalk and long hilum. 



Indian Territory to Kansas and Dakota, west 

 to Colorado and Utah. May-June. 



