FLORA OF THE DISTRICT OF COLUMBIA. 261 



2. Viburnum affine Bush. 



Frequent on rocks and in woods on both sides of the river about Great Falls. May; 

 fr. July-Sept. Northeastern N. Amer. 



Our plant is the pubescent form, V. affine hypomalacum Blake. ( V. pubescens of 

 authors.) 



3. Viburnum dentatum L. 



Common in moist ground and swamps. May-June; fr. July-winter. North- 

 eastern U. S. 



4. Viburnum scabrellum (Torr. & Gray) Chapm. 



Common; in drier land, fence rows, and edges of woods. June. Southeastern U. S. 



6. Viburnum pubescens (Ait.) Pursh. 



Common in copses and fence rows. June; fr. Aug.-wintor. Eastern U. S. (F. 

 venosum Britton; V. venosum canbyi Rehder.) 



This and the last preceding are closely related to V. dentatum and puzzling inter- 

 mediate forms occur. 



6. Viburnum cassinoides L. 



In bogs now or formerly sphagnous; north and east of Washington. May-June; 

 fr. Aug. -winter. Eastern N. Amer. 



7. Viburnum nudum L. 



With the last, but also in ordinary swampy or wet places. May-June; fr. Sept.- 

 May. Eastern U. S. 



8. Viburnum prunifolium L. Black haw. 

 Abundant in a variety of situations. Apr. -June; fr. July-Apr. Eastern U. S. 

 A shrub, or a small tree with trunk as much as a foot in diameter. 



6. SAMBTJCTIS L. 

 1. Sambucus canadensis L. Elder, 



Abundant in wet places. May-June; fr. July-Aug. Eastern N. Amer. 



146. VALERIANACEAE. Valerian Family. 



Plants perennial, spreading by slender runners; stem leaves pinnate; corolla very 



slender, 1-2 cm. long 1. VALERIANA. 



Plants annual; stem leaves narrow, simple; corolla 2-3 mm. long. 



2. VALERIANELLA. 

 1. VALERIANA L. Valerian. 



1. Valeriana pauciflora Michx. 



Shaded alluvial flats; locally common at a few localities along the Potomac from 

 High Island to Plummers Island, especially on the islands. May. Eastern U. S. 



2. VALERIANELLA Hill. Lamb's lettuce. Corn salad. 



Corolla bluish, the color evident in the subpersistent corollas of fruiting specimens. 



Fiuit flattened, rounded 1. V. locusta. 



Corolla whitish. 



Fruits roundish or saucer-shaped, the sterile cells inflated 2. V. woodsiana. 



Fruits oblong to ovate in outline. 

 Fertile cell of the fruit distinctly broader than the sterile one, the fruit triangular 



in cross section 3. V. chenopodifolia. 



Fertile cell as broad as the sterile ones, the fruit 4-angled in cross section. 



4. V. radiata. 

 1. Valerianella locusta (L.) Betcke. 



Damp meadows, old fields, and thickets; not uncommon, especially along the 

 Potomac. Apr.-May. Naturalized from Eur. (Fedia olitoria of Ward's Flora.) 



