174 American Midland Naturalist Monograph No. 2 



7. Branches mostly opposite or whorled; racemes short-peduncled; flowers 

 green or greenish; dry soil throughout 111., except the s. counties. 

 July-Sept P. verticdlata L. 



7. Branches mostly alternate; racemes long-peduncled; flowers purplish or 



greenish purple; woods and fields, s. 111. June-Aug 



P. ambigua Nutt. 



94. EuPHORBiACEAE J. St. Hil. — Spurge Family 



I. Flowers not in an involucre; calyx of 3-5 sepals; sap watery. 



2. Pubescence of stellate hairs. 



3. Flowers in spikes or glomerules; ovary 3-(2-4)-loculed 1. Crolon 



3. Flowers scattered on the branchlels; ovary 1-loculed 2. Croionopsis 



2. Pubescence, if any, of simple hairs. 



4. Leaves serrate; stamens usually 8; styles many-cleft; bracts of the pistillate 



flowers cleft 3. Acalvpha 



4. Leaves entire; stamens usually 3; styles simple; bracts of the pistillate flowers 



not cleft - 4. Ph\^llanlhus 



1. Flowers in a cup-shaped calyx-like involucre; sepals rudimentary; sap milky. 



5. Leaves opposite, oblique at base 5. Chamaes\)ce 



5. Leaves not oblique at base, alternate or opposite. 



6. Inflorescences in a several-rayed umbel; stipules none 6. Euphorbia 



6. Inflorescences cymcse ; stipules gland-like 7. Poinsetlia 



I. Croton L. 



1 . Leaves serrate; staminate flowers with a 4-parted calyx, 4 petals, a 4-rayed 

 disk, and 8 stamens; pistillate flowers with a 5-parted calyx; styles 3, 



bifid; sandy soil, adv. from s. U.S. Aug. -Oct. Sand Croton 



C. glaiidulosiis L. 



1 . Leaves entire. 



2. Capsules clustered, erect, depressed-globose, 7-9 mm. in diameter; styles 



3, bifid or trifid; stamens 10-14; sandy soil, probably adv. from s. US. 



Aug. -Sept C. capitatiis Michx. 



2. Capsules mostly solitary, pendent, ovoid, 3-4 mm. long; style none, the 



stigmas 2, bifid; stamens 3-8; roadsides and fields, chiefly in the s. half 



of 111. July-Oct C. monanthogynus Michx. 



2. Crotonopsis Michx. 



1. Leaves lanceolate; fruit ovoid; fields and open woods, local. July-Sept 



C. elliptica Willd. 



1. Leaves linear-lanceolate; fruit ellipsoid; dry sandy soil, s. 111., rare. July- 

 Sept C. linearis Michx. 



3. AcALYPHA L. — Three-seeded Mercury 

 1. Leaves slender-petioled; pistillate bracts with lanceolate, acute lobes. 



2. Stem with short, curved hairs, or nearly glabrous; bracts of the pistillate 

 flowers 5-7- (or rarely 9-) -lobed, bearing a few whitish stipitate glands 

 (at least when young), or nearly glabrous; woods, fields, and roadsides, 



common. July-Oct. {_A. virginica sensu auth.^ex p.} 



A. rhomhoidea Raf. 



