FLORA OF THE DISTRICT OF COLUMBIA. 205 



3. Hypericum perforatum L. Common St. John's-wort. 

 Fields and waste places; frequent. July. Eastern U. S.; naturalized from Eur. 



4. Hypericum denticulatum Walt. 



Damp places; common. July. Eastern U. S. (H. punctatum Lam.; H. corym- 

 bosum Muhl.) 

 Usually taller than H. perforatum and not eo much branched. 



6. Hypericum mutilum L. 



Low grounds; frequent. Aug.-Oct. Eastern N. Amer. 



A small-flowered small-capsuled species (capsules 1-2 mm. long), with 4-angled 

 branchlets. A specimen of this species was reported by Steele as H. majics (A. Gray) 

 Britton. 



6. Hypericum canadense L. 

 Wet or dry soil; frequent. Aug.-Oct, Eastern N. Amer. 



3. SAROTHRA L. 

 1. Sarothra gentianoides L. 



Sandy or rocky soil; frequent. Aug.-Sept. Eastern U. S. {Hypericum sarothra 

 Michx.; H. gentianoides B. S. P.) 



4. TRIADENTJM Raf. 



1. Triadenum virginicum (L.) Raf. Marsh St. John's-wort, 



Marshes or swamps; frequent north and east of Washington, July-Aug. Eastern 



N. Amer, {Elodea virginica Nutt. ; Hypericum virginicum L.) 

 Distinguished from our other members of the family by the distinct reddish tinge, 



and by the large leaves, which are frequently 4 cm. long, 



104. ELATINACEAE. Waterwort Family. 



1. ELATINE L, Waterwort. 



1, Elatine americana (Pursh) Am, 



Reported by Holm from near Chain Bridge, on the Virginia shore of the Potomac. 

 Widely distributed in N. Amer, 



It may be found near or submerged in water; characterized by membranaceous 

 stipules between opposite leaves, and minute axillary flowers. 



105. CISTACEAE. Rock-rose Family. 



Petals 5, yellow, crumpled in bud, fugacious or sometimes wanting; style short; 



ovules numerous in the petal-bearing flowers 1. HELIANTHEMITM. 



Petals 3, not yellow, flat in bud, persistent; style none; pod partly 3-celled, the 



imperfect partitions bearing broad 2-seeded placentae 2. LECHEA. 



1. HELIANTHEMUM Mill. 



1. Hellanthemum canadense (L.) Michx, Frostweed, 



Dry soil; frequent northeast of Washington, May, Eastern U. S. {Crocanthemum 



canadense Britton.) 

 An erect hoary-pubescent perennial herb, with oblong-linear leaves, the flowers of 



two kinds, the early ones large and solitary, the later ones small and clustered. 



2. LECHEA L. Pinweed. 



Leaves of the basal shoots elliptic or oblong, not more than three times as long as 

 broad. 



Outer sepals exceeding the inner ones; panicle very leafy 1. L. minor. 



Outer sepals shorter than the inner; panicle usually not very leafy. 



2. L. racemulosa. 



