FLORA C'F THE DISTRICT OF COLUMBIA. 229 



2. Bartonia paniculata (Miclix.) Robinson. 



Sphagnum bogs; rare or probably overlooked. Aug.-Sept. Eastern U. S. 



2. OBOLAEIA L. 



1. Obolarla virginica L. Pennywort. 



Woodd; frequent. March-June. Eastern U. S. 



3. SABBATIA Adan«. Rose-gentian. 



Corolla 8-12-lobed 1. S.dodecandra. 



Corolla 5-lobed. 

 Branches opposite, sharply angled; leaves broadly ovate, clasping at the base; 



calyx lobes shorter than the corolla 2. S. angiilaris. 



Branches alternate, nearly terete; leaves linear or linear-lanceolate, narrowed at 

 the base; calyx lobes equaling or longer than the corolla. . .3. S. cainpanulata . 



1. Sabbatia dodecandra (L.) B. S. P. 



Along the Potomac below Alexandria {Titus Ulke). Eastern U. S. 



2. Sabbatia angularis (L.) Pur.^h. 



Dry or moist fields. July-Sept. Eastern N. Amer. 

 Plants with white corollas are sometimes found. 



3. Sabbatia campanulata (L.) Torr. 



Low meadow near Falls Church, July, 1888 (C Knisley). Eastern U. S. {S. 

 gracilis Salisb.) 



4. GENTIANA L. Gentian. 



Corolla greenish wliite, striped with purple; lower leaves obovate, rounded at the apex ; 



margins of the calyx lobes and leaves glabrous or nearly so 1. G. villosa. 



Corolla blue; leaves mostly lanceolate and broadest below the middle, usually very 

 acute; margins of the calyx lobes and leaves finely hairy. 

 Corolla rather deeply lobed, the lobes equaling or longer than the toothed plaits 



between them 2. G. saponaria . 



Corolla very shallowly lobed, the lobes small, often shorter than the plaits. 



3. G. andrewsii. 



1. Gentiana villosa L. Striped gentian.. 

 Woods or thickets; frequent. Aug.-Oct. Eastern U. S. {G. ochroleuca Froel.; 



Dasystephana villosa Small.) 



2. Gentiana saponaria L. Bottle gentian. 

 Low woods and thickets; frequent. Sept.-Oct. Eastern N. Amer. {Dasysteph- 

 ana saponaria Small.) 



3. Gentiana andrewsii Griseb. Closed gentian. 

 Low woods or thickets; rare. Sept.-Oct. "^Northeastern N. Amer. {Dasystephana 



andrewsii Small.) 



This and the preceding species intergrade, and the two are doubtfully distinct. 



Nymphoides peltatum (Gmel.) Britten & Rendle {N. nyinphaeoides Britton), float- 

 ing heart (of the allied family Menyanthaceae), was formerly well established in the 

 fish ponds, Potomac Park; the ponds have been filled, however, and the station 

 destroyed. >iative of Eur. and Asia. 



127. APOCYNACEAE, Dogbane Family. 



Plants erect; leaves not evergreen; flowers in branched cymes; corolla 8 mm. long 

 or smaller white, greenish white, or pink 1. APOC YNITM . 



Plants creeping; leaves evergreen; flowers solitary in the axils of the leaves, on long 

 slender pedicels; corolla about 2 cm. long, blue 2. VINCA. 



