EUCALYPTUS TREES. 507 
Plectronia ventosa, Linné.—South Africa. A hedge- 
bush like P. ciliata, Sonder, and P. spinosa, Klotzsch. 
Poa Abyssinica, Jacquin.—The Teff of Abyssinia. 
An annual grass. The grain there extensively drawn 
into use for bread of an agreeable, acidulous taste. 
Poa Canadensis, Beauvois.—The Rattlesnake-grass 
of North-east America. A valuable swamp - grass. 
Polygala crotalaroides, Hamilton.—Temperate Him- 
alaya. Praised as an ophidian alexipharmic. To 
several other species both of the eastern and western 
hemispheres similar properties are ascribed, but we 
are almost entirely without any reliable medical tes- 
timony on these and many other vegetable antidotes 
against snake poison. 
Polygaster Sampadarius, Fries. — South- eastern 
Asia. One of the most palatable of all truffles. 
Polygonum tinctorium, Loureiro.—Japan and Chi- 
na. An annual herb, deserving attention and local 
trials here, as yielding a kind of indigo. Its growth 
would be vigorous. 
Prunus ilicifolia, Nuttall. — California. In deep, 
rich soil, valuable for evergreen hedges of intricate 
growth. 
Prunus Mahaleb, Linné.—Middle and South Eu- 
rope. It deserves some attention on account of its 
scented seeds, and also odorous wood, the latter used 
in turnery for pipes and other articles. 
Psidium acidum, Martius.—Higher regions on the 
Amazon river. A tree, 30 feet high ; its guava fruit 
pale yellow, and of apple size. 
Psidium chrysophyllum, F. von Mueller. (Abbe- 
villea chrysophylla, Berg.)—The Guabiroba do mato 
of South Brazil. -This tree attains also a height of 
