168 American Midland Naturalist Monograph No. 2 



8. Leaflets linear. 



10. Spikes dense, capitate; open woods in the n. half of the state. Aug.- 



Sept L. longijolia DC. 



10. Spikes slender, loose; prairie soil, rare; known in III. from Mc- 



McHenry and Winnebago counties. Aug.-Sept 



L. leptostachya Enge'm. 



1. Annuals with scarious ovate-lanceolate stipules and bracts; calyx-lobes as 

 broad as long; stems erect; flowers solitary or 2 or 3 in the axils; roadsides 



and fields; introd. from Asia. Aug. -Oct. Japanese Bush-clover 



L. striata (Thunb.) H. & A. 



26. Stylosanthes Sw. — Pencil-flower 



S. biflora (L.) BSP. Dry soil in woods, s. Ill,; known from Saline, Gal- 

 latin. Johnson, and Pope counties. June-Aug. 



27. ViciA L.— Vetch 



1. Flowers solitary or in pairs, axillary, nearly sessile; annuals. 



2. Flowers 2-2.5 cm. long; leaflets oblanceolate to oval; pods brown; fields, 

 and waste places, escaped from cult.; introd. from Eur. July- Aug. 

 Spring Vetch V. sativa L. 



2. Flowers 10-18 mm. long; leaflets linear to linear-oblong; pods black when 



mature; fields and waste places, escaped from cult.; introd. from Eur. 

 July-Aug. Common Vetch V. angustifolia (L.) Reich. 



1. Flowers in 3-40-flowered racemes on axillary peduncles. 



3. Flowers 1-2 cm. long. 



4. Racemes 15-40-flowered, dense, unilateral. 



5. Calyx gibbous at base; leaflets narrowly elliptical; flowers 14-18 mm. 

 long, crimson, fading to blue; pods 2.5-3.5 cm. long; seeds 3-4 

 mm. in diameter, dark brown; roadsides and fields, common; nat. 

 from Eur. June-Aug. Winter Vetch V. villosa Roth 



5. Calyx not gibbous; leaflets linear-oblong; flowers 9-12 mm. long, 



bluish-purple; pods 1.5-2 cm. long; seeds 2.5 mm. in diameter, 

 black; roadsides and fields, occasional; introd. from Eur. June- 

 Aug. Tufted Vetch V. cracca L. 



4. Racemes 3-20-flowered, loose; leaflets oval or elliptical. 



6. Corolla 1.5-2 cm. long, bluish purple; meadows and thickets, chiefly 



in the n. half of the state. June-July. American Vetch 



V. amcricana Muhl. 



6. Corolla about 1 cm. long, white; woods in the n. part of the state; 

 known from Lake, McHenry, Cook, and La Salle counties. May- 

 June. Carolina Vetch V. caroltn'iana Walt. 



3. Flowers 3-4 mm. long, pale bluish; pods 1-2-seeded; leaflets linear; waste 



places, occasional; nat. from Eur. May-Aug V. hirsuta (L.) Koch 



28. Lathyrus L.— Wild Pea 

 1. Flowers purple, or purplish to pink or white. 

 2. Leaflets 4-14. 



3. Stipules much smaller than the leaflets; corolla 1-L5 cm. long. 



