ISO THE PLANT LIFE OF MARYLAND 



its clusters of whitish flowers. Occurring frequently on the shrubs 

 is a Cuscuta, which appears to find the conditions altogether suitable, 

 judging by its luxuriance. 



The phanerogamic representatives of the parasites which are 

 found in this district may be briefly considered here. Of the genus 

 Cuscuta at least two species occur, Cuscuta gronovii on various 

 plants found in river valleys and low grounds generally, and the 

 species referred to above, Cuscuta polygonorum usually growing on 

 Iva and Baccharis near salt water. Phoradendron flavescens, the 

 mistletoe, occurs in the "meadow" districts, e. g. southeast of West 

 River, Anne Arundel County, and appears to prefer Black Gum as 

 a host. Leptamnium virginiaiium, Beech Drops, occurs on the roots 

 of Fagus in many parts of the region. This plant belongs to the 

 class of root-parasites, as has long been suspected and recently es- 

 tablished by Cooke and Schiveley.* The genus Melampyrum con- 

 tains some root-parasites, as the researches of Heinricher have 

 shown. Melampyrum lineare occurs plentifully in dry woods in 

 our region, but of the specimens dug up none were found to be 

 attached to other plants, though the writer is informed that farther 

 north the plant behaves as a root-parasite. This species is prob- 

 ably able to live an independent existence. The species of Gerardia 

 are said to be more or less root-parasitic, hut the point has not been 

 investigated in this connection. Comandra umbellata, reported from 

 the vicinity of Baltimore, was not collected by the writer. Related 

 to parasites are those plants which owe their nutrition to symbiotic 

 fungi. Among these, Monotropa uniflora and Hypopitys hypopitys 

 are distributed throughout the area, while the species of Corallorliiza 

 are not so common {Corallorliiza multi/lora was collected near Bowie, 

 Prince George's County). 



Typlia association. — In less salt situations than any of the pre- 

 ceding, though by no means in the drier parts of a marsh, generally 

 occur more or less extensive groups of Typlia angustifolia or in some 

 cases Typlia latifolia. In cases where the groups occur near the 

 mouth of a stream, the smaller proportion of salt is to be accounted 



♦Observations on the structure and development of Epiphegus virginiana. 

 Trans, and Proc. Bot. Soc. of Penna., vol. i, 1904, pp. 352-398. 



