Jones: Flora of Illinois, 117. Cornaceae 193 



2. HiPPURlS L. — Mare's-tail 



H. vulgaris L. Ponds and streams, rare. Known from Lake and McHenry 

 counties. June-Aug. 



3. Proserpinaca L. — Mermaid-weed 

 P. palustris L. Ponds and slow streams, n.e. 111. Known from Lake, Cook, 

 and Du Page counties. July-Sept. 



117. Cornaceae Link — Dogwood Family 



1 . Flowers 4-merous, perfect; leaves opposite (except Cornus alfernifolia) I. Cornus 



1 . Flowers 5-merous, polygamous; leaves alternate 2. A/pssa 



1. Cornus L. — Dogwood 



(SviJa Opiz) 



1. Flowers cymose or paniculate, without an involucre; stone of the fruit sub- 

 globose. 



2. Leaves alternate; woods, usually near streams, chiefly in the n. two-thirds 



of the state. May-June. Alternate-leaved Dogwood 



C. alternifolia L. f 



2. Leaves opposite. 



3. Lower surface of blades pale, strigose, strigillose, or glabrescent, the 

 trichomes wholly appressed. 

 4. Leaves pale and microscopically farinose or pulverulent beneath. 

 5. Young twigs strigillose to glabrous. 



6. Mature twigs bright red; cyme dense, flat-topped; stone com- 

 pressed; swampy ground, local. June-July. Red-osier Dogwood 



C. stolonifera Michx. 



6. Mature twigs gray or brown; cyme loosely-flowered, convex; 



stone subglobose, not compressed; along roads, and in low 



ground along streams, common. May-June. [C. paniculctta 



L'Her.; C. femina Mill.} Gray Dogwood ..C. racemosa Lam. 



5. Young twigs tomentulose; moist ground, common. May-June. [C. 



amotnum sensu auth., non Mill.] Pale Dogwood 



_.-C. obliqua Raf. 



4. Leaves green beneath, not at all farinose, low woods, chiefly s. 111. 



June C stricta Lam. 



3. Lower surface of blades with loose, partly spreading pubescence, at 

 least on the veins. 

 7. Leaves roundish-ovate, woolly pubescent beneath at maturity; woods, 

 n. 111., extending southw. to Kankakee and La Salle counties. May. 



[C. circinata L'Her.] Round-leaved Dogwood C. rugosa Lam. 



7. Leaves lance-ovate. 



8. Leaves finely pubescent above; lake shores, n. 111. May-June. 



Bailey's Dogwood C. baileyi Coult. & Evans 



8. Leaves scabrous above; moist ground on roadsides or along 

 streams, common. May-June. Rough-leaved Dogwood. [C. as- 

 perifolia of auth., not Michx.] C drummondi C. A. Mey. 



