174 American Midland Naturalist Monograph No. 7 



13. Spermolepis Raf. 



S. inermis (Nutt.) Math. & Const. Sandy soil, local; southward to 

 Macoupin Co. June. 



14. Zizia Koch — Golden-alexanders 



1. Basal leaves ternately divided; fruit ellipsoid, 3.5-4 mm long at 

 maturity; roadsides, fields, meadows, open woods, common; 

 rare in the southern counties. May-June Z. aurea (L.) Koch 



1. Basal leaves ovate or suborbicular, deeply cordate, crenate; fruit 

 oval, 3 mm long; Boone, Cook, De Kalb, Lee, McHenry, and 

 Winnebago counties. [Thaspium trifoliatu?7i var. apterum A. 



Gray; Z. cordata sensu auth., non (Walt.) Koch] 



Z. aptera (A. Gray) Fern. 



15. Taenidia (Torr. & Gray) Drude 



T. integerrhna (L.) Drude. Woods and thickets, often on eroding 

 clay banks, common throughout 111. May- June. 



16. Conium L. — Poison-hemlock 

 C. maculatum L. Waste places; nat. from Eur. June-July. 



17. Ptilimnium Raf. — Bishops-weed 

 1. Fruit 2-4 mm long and broad; leaves petioled, the segments 5-10 



mm long, crowded, appearing verticillate; swampy ground, s. 



111., rare. June-Oct. \P. capillaceurn sensu auth., non (Michx.) 



Raf.] P. costatum (Ell.) Raf. 



1. Fruit about 1.5 mm long and 1 mm wide; leaves sessile or very 



short-petioled, the segments 1-6 cm long, alternate or opposite; 



swamps, s. 111., rare. May-Sept P. nuttallii (DC.) Britt. 



18. Sium L. — Water Parsnip 

 S. suave Walt. Wet ground or occasionally in water, locally 

 throughout 111. June-Aug. [S. cicutaefolium Schrank]. 



19. Cicuta L. — Cowbane 

 1. Leaflets narrowly linear; axils of the upper leaves bearing bulblets; 



swamps in the northern half of the state. July-Sept 



C. bulbifera L. 



1. Leaflets lanceolate; axils of the leaves never bearing bulblets; 



swamps and wet meadows, locally throughout 111. June-Aug. 



Water Hemlock C. maculata L. 



20. Thaspium Nutt. 

 1. Flowers deep yellow or sometimes purple; stem glabrous; basal 

 leaves either cordate or temate; woods and river banks, com- 

 mon. May-June. [T. trifoliatum var. flavum Blake; Zizia 



sylvatica Benke; T. aureum sensu auth., non (L.) Nutt.] 



T. trifoliatum (L.) A.Gray 



