204 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



2. Hibiscus militaris Cav. Rose mallow . 

 Along the Potomac. July-Aug. Eastern U. S. 



3. Hibiscus palustris L. Swamp mallow. 

 Tidal marshes along the Potomac and Eastern Branch. July-Aug. Southeastern 



U. S. 



This species has been confused with the pink-flowered II. moscheutos L., found 

 north of our region. 



Gossypium hirsutum L. t upland cotton, is occasionally found in freight yards and 

 along railroad tracks. As cotton is easily killed by freezing temperatures, the plants 

 do not survive the winter. 



103. HYPERICACEAE. St. John's-wort Family. 



Sepals 4, in unequal pairs; petals 4 1. ASCYBTTM. 



Sepals and petals 5. 

 Petals yellow, convolute in bud. 



Leaves normal, not reduced to scales 2. HYPERICUM. 



Leaves reduced to minute appressed scales 3. SAROTHRA. 



Petals pink or greenish purple, imbricate in bud 4. TRIADENUM. 



1. ASCYRUM L. 



Plants erect, with few erect branches, 30-60 cm. high; leaves clasping, oval or broadly 

 oblong, thick; styles 3 or 4; pedicels without biacta near the flower. .1. A. stans. 



Plants diffusely branched, 12-25 cm. high; leaves sessile, oblong or obovate, narrow, 

 thin; styles 2; pedicels 2-bracted near the flower 2. A. hypericoides. 



1. Ascyrum stans Michx. St. Peter's-wort. 

 Dry sandy soil; frequent northeast of Washington. Aug. Eastern U. S. 

 Flowers showy, 1-2 cm. broad. 



2. Ascyrum hypericoides L. St. Andrew's cross. 

 Sandy or rocky barrens; common. July-Sept. Eastern U.S. (A. crux-andreaeL.) 

 Flowers not so conspicuous as in the preceding, usually about 1 cm. broad. The 



plant derives its common name from the arrangement of sepals and petals in the form 

 of a St. Andrew's cross. 



2. HYPERICUM L. St. John's-wort. 

 Plants tall shrubs. 



Flowers 10-20 mm. broad; pods 10-15 mm. long 1. H. prolificum. 



Flowers 8-12 mm. broad ; pods 5-8 mm. long 2. H. densiflorum. 



Plants herbs, sometimes woody at the base. 

 Stamens numerous (15-40); flowers 7-25 mm. broad; plants perennial. 

 Leaves linear or oblong, not conspicuously black-dotted, 8-23 mm. long, 1-8 mm. 



wide 3. H. perforatum. 



Leaves broadly oblong, oval, or ovate-lanceolate, conspicuously black-dotted. 



25-75 mm. long, 8-16 mm. wide 4. H. denticulatum. 



Stamens few (5-12); flowers 1-7 mm. broad; plants usually annual. 



Leaves ovate, oval, or oblong, 5-7 -nerved S. H. mutilum. 



Leaves linear, 3-nerved 6. H. canadense. 



1. Hypericum prolificum L. Shrubby St. John's-wort. 

 Sandy or rocky soil; common. July. Eastern U. S. 



Internodes of the younger branches moie or less exposed. 



2. Hypericum densiflorum Pursh. 



Pine barrens; rare; reported from Surrattsville and Berwyn. Eastern U. S. 

 Much branched above, the branches leafy, the internodes hardly visible. 



