200 MISSISSIPPI STATE GEOLOGICAL SURVEY [Buli. 
Hypercium perforatum L. 
Moist shaded ground. Oxford; Hinds Co. 
Gecl. Sur. Herb. 
TRIADENUM Raf. 
Triadenum petiolatum Walt. (Elodes petiolata Pursh.) Marsh 
St. Johnswort. 
Edges of marshes and swamps. Rankin Co. (Hilg. Ms.). 
July. 
Triadenum Virginicum (L.) Raf. (Elodes campanulata Pursh.) 
Virgina Marsh St. John’s Wort. 
Low wet places, perhaps throughout the state. Oxford; 
Taylorsville; Bay St. Louis. July. 
Geol. Sur. Herb. Allison Herb. 
CISTACEAE. Rock Rose Family. 
HELIANTHEMUM Pers. 
Helianthemum arenicola Chapm. Seaside Rock Rose. 
Drifting sand near the seashore (Mohr). April-May. 
Helianthemum Georgianum Chapm. Georgia Rock Rose. 
Open sandy hillsides. Along the coast (Dr. T. P. Bailey) ; 
Coastal Islands (Tracy). May-June. 
Helianthemum corymbosum Michx. CorymbedRock Rose. 
Dry sands near the coast. Coastal Islands (Tracy). April. 
Helianthemum rosamarinifolium (Pursh). 
Dry sandy banks (Mohr). August. 
Helianthemum Carolinianum (Walt) Michx. (Cistus Carolinia- 
nus Walt.) Carolina Rock Rose. 
Dry sandy soil. Oxford; Carrollton. March, 
Geol. Sur. Herb. 
LECHEA IL. Pinweed. 
Lechea minor L. (Ul. thymifolia Michx.) Thyme-Leaved 
Lechea. 
Light sandy soil in the coastal regions. Coastal Islands 
(Tracy). August. 
