THE AMERICAN BOTANIST 39 



the whole categor)- is otic of the e\etiiniL,^ primroses, Oenothera 

 l-'rasi'ii. 'Phe \vor>t i)est one can get into his lawn is the com- 

 mon moneywort {Lysi)iiaclii(i iiiiiiiulariu.) 



Poisoxous MmKWKKDS. — We ha\e already called atten- 

 tion in these pages to the fact that a western species of milk- 

 weed, .Isclcpias galioidcs, is poisonous to stock. Further in- 

 vestigations by the United States Department of Agriculture 

 indicate that se\eral other species or forms closely related to 

 the whorled milkweed {Asclcpias vcrticiUata)' oi the Eastern 

 States are also poisonous. These forms are wide-spread in 

 the West. Asclepias galioides, however, is the most venemous 

 of the lot, being recorded as ten times more poisonous than 

 A. TcrticiUata \;ir. Ccyerv of the Great Plains region. In the 

 Litter region is also found A. puuiila and on the Pacific Coast 

 from California to Washington occurs A. Mexicana. A. gal- 

 ioidcs is found in Arizona, New Mexico and contiguous ter- 

 ritory. Fortunately the plants are not readily eaten by cattle 

 and sheep and few cases of poisoning ordinarily occur, but 

 when stock have difficulty in finding other food they may eat 

 tlie plant with fatal results. It may be noted that the common 

 milkweed [Asclcpias syriaca) is regularlv used as a jiot-herb 

 in Eastern America and appears to have no poisonous proper- 

 ties. The swamp milkweed {Ascclepias incarnata), however, 

 is looked on with suspicion and i)ractically never gathered. 



Arm Soils. — It is an obvious fact that jjlants do not 

 grow just anywhere. Each species is closely related to its 

 etnironment. One grows only in sandv places, another on 

 limestone rocks, others in clay and still others in muck or jieat. 

 In general, plants do not tliri\e in the la>t mentioned soil be- 

 cause of its acidity and the plants that are able i^< live in such 

 places form a \ ery interesting groii[). .\mong them are the 



