192 American Midland Naturalist Monograph No. 2 



puberulent; roadsides, occasional; native w. of the Mississippi R. 

 June-July. [Hartmannia speciosa (Nutt.) Small] White evening- 

 primrose O. speciosa Nutt. 



1. Stem-leaves linear-filiform; stigma shallowly lobed; petals 3-4 mm. long; 

 capsules ellipsoid, sessile, 4-angled, 4-6 mm. long; sandy soil, s. 111., rare; 

 known from Jackson and Johnson counties. May-June. [^Kneiffia linifolta 



(Nutt.) Spach; Peniophylliun linifoliutn (Nutt.) Pennell} 



O. linifolia Nutt. 



5. Gaura L. — Butterfly-weed 

 1. Petals 2-3 mm. long; anthers oval, attached near the middle; fruit fusiform, 

 4-nerved, glabrous, 6-8 mm. long; roadsides, rare; adv. from w. U.S. 

 June-July G. parvi flora Dougl. 



1. Petals 7-9 mm. long; anthers linear, attached near the base; fruit 4-angled, 



pubescent, 5-6 mm. long; fields and open woods. July-Sept 



G. biennis L. 



6. CiRCAEA L. — Enchanter's-nightshade 



1. Stem 30-60 cm. tall; leaves shallowly undulate-dentate, usually rounded at 

 the base; fruit 2-Ioculed, 4 mm. long at maturity; woods, common. June- 

 July. [C. lutettana of auth., not L.J C. latifolia Hill 



l.Stem 10-30 cm. tall; leaves sharply dentate, mostly cordate; fruit 1-locuIed, 

 2 mm. long; moist banks and ravines in deep woods, n. 111. Lake BluflF, 



Hill; Elgin, Vasey; Jo Daviess Co., Pepoon & Moffatt. June-July 



_ C. alpina L. 



116. Haloragidaceae R. Br. — ^Water-milfoil Family 

 1 . Leaves whorled (rarely subopposile or alternate). 



2. Leaves (at least the immersed ones) pmnately dissected; stamens 4-8; fruit 4-lobed 

 1. M\!riophyllum 



2. Leaves entire, linear; flowers perfect; stamen I; sepals and petals none; fruit 1- 

 loculed -..2. Hippuris 



1. Leaves alternate, dentate or pectinate-pinnatifid ; stamens 3-4; fruit 3-angled 



3. Proserpinaca 



1. Myriophyllum L. — Water-milfoil 



1. Carpels rounded and smooth on the back. 

 2. Floral leaves (bracts) entire or denticulate. 



3. Leaves verticillate in fours or fives; lakes and slow streams, n.c. 111. \M. 



exalbescens Fern.} M. spicatum L. 



3. Leaves chiefly scattered, or absent from the flowering stems; muddy 



shores and shallow water, rare M. hiiniilc (Raf.) Morong 



2. Floral leaves pinnatifid or pectinate; leaves verticillate in threes and fours; 

 lakes and slow streams, local M. verticillatum L. 



1. Carpels 2-keeled and roughened on the back; stamens 4. 



4. Floral leaves (bracts) ovate or lanceolate, serrate; ponds and slow 



streams, local M. hcterophylluni Michx. 



4. Floral leaves linear, pectinate; ditches and muddy shores, chieflv in w. 111. 



[M. scabratum Michx.] M. pinnatum (Walt.) BSP. 



