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FLORA OF THE DISTRICT OF COLUMBIA. 255 



1. LEPTAMNIUM Raf. 



1. Leptamnium virginianum (L.) Raf. Beechdrofs. 



Parasitic on roots of the beech in moist woods; common. Aug.-Oct. Eastern N. 

 Amer. (Eplphagus virginiana Barton.) 



2. THALESIA Raf. 



1. Thalesia uniflora (L.) Britton. Ghost-pipes, 



Moist woods and thickets; common. May. Eastern N. Amer. (Aphyllon uni- 



florum Torr. & Gray.) 

 A tuft of the plants is shown in plate 37A. 



3. CONOPHOLIS Walk. 



1. Conopholis americana (L. f.) Wallr. Squaw-root. 



Rich hilly woods; common. May. Eastern N. Amer. 

 A tuft of the plants is shown in plate 34A. 



4. OROBANCHE L. 



1. Orobanche minor J. E. Smith. Broom-rape. 



Parasitic on clover; common. May-June. N. J. to Va.; naturalized from Eur. 



140. PINGTJICuXACEAE. Bladderwort Family. 



Plants growing in water, the stems creeping or floating, branched. Bracts of the stems 

 attached by the base 1. UTRICULARIA. 



Plants growing in soil, the stems erect, simple. 

 Bracts of the stems attached by the middle; bracts at the base of the pedicel without 



bractlets; calyx not inclosing the capsule 2. SETISCAPELLA. 



Bracts attached by the base; bracts at the base of the pedicel accompanied by a 



pair of bractlets; calyx inclosing the capsule 3. STOMOISIA. 



1. UTRICULARIA L. Bladderwort. 



Stems creeping in the bottom of water; corolla 4-6 mm. long; flowers 1-4 on each 

 scape 1. TJ. gibba. 



Stems free-floating except for a single point of attachment; corolla 13-20 mm. long; 

 flowers 6-20 on each scape 2. U. macrorhiza. 



1. Utricularia gibba L. 



Pools along the upper Potomac. July-Sept. Eastern N. Amer. 



2. Utricularia macrorhiza LeConte. Zigzag bladderwort. 

 Hunting Creek. Aug. Widely distributed in N. Amer. ( U. vulgaris of American 



authors.) 



2. SETISCAPELLA Barnhart. 



1. Setiscapella subulata (L.) Barnhart. 

 Wet sandy soil; occasional. May-July. Eastern IT. S. ( Utricularia subulata L.) 



3. STOMOISIA Barnhart. 



1. Stomoisia virgatula Barnhart. 

 Swamp near Suitland. N. Y. to Miss. ( Utricularia virgatula Barnhart.) 



141. ACANTHACEAE. Acanthus Family. 



Flowers in dense long-stalked heads or spikes, small; plants glabrous; leaves linear- 

 lanceolate 1. DIANTHERA. 



Flowers borne in the axils of the leaves, large; plants more or less hairy; leaves ovate 

 or oblong 2. RTJELLIA. 



