BOTANICAL NOTICES OF NEW PLANTS. 



77 



afterwards carefully washed, and then placed in pure water, in which their 

 x'oots excreted the disagreeable matter with which they were gorged. 



The effects of these excretions on vegetation have been investigated by 

 vegetable physiologists, who have found that if the Lythrum salicaria be planted 

 near the willow, the truffle near the oak or the hornbeam, they become unhealthy 

 and die, in consequence of the excretion from the' roots being noxious to them. 



These observations have been confirmed by Macaire in the following maimer : 

 — He placed kidney-beans in water in which was mixed some excretions from 

 the' roots of other plants of the same species. On examining them he found 

 that, instead of affording the plants nourishment, they became languid and died. 

 He placed other Leguminos® in the same solution mixed with the same excre- 

 ments, and they were observed to flourish luxuriantly. 



These facts sufficiently prove that the sowing of grain, &c, repeatedly on 

 the same soil where it becomes languid and unhealthy, does not arise from 

 poverty of the soil, but from excrementitious particles exuded by the root. 



BOTANICAL NOTICES OF NEW PLANTS. 



DICOTYLEDONES. 



RANUNCULACEiE. 



P^eonia Brownii. Douglas's Californian Paeony. Bot. Reg. N. S. 30. 

 This is an extremely rare and curious plant, introduced several years ago by the 

 London Horticultural Society, to which establishment it was sent by Mr. 

 Douglas. The petals are of a brownish red colour, according to the plate of the 

 Bot. Reg., but reddish purple according to Nuttall, and the sepals a brownish 

 green. Its carpels are five in number. The diameter of the flower is about two 

 inches. It is not showy, but is deserving of cultivation, from its singular and 

 curious appearance. It was considered, until this species was discovered, that 

 the genus Pseonia was exclusively Asiatic or European, but this species found 

 in the new world has extended its limits. / 



It was found by Douglas, near the limits of perpetual snow, on the 

 subalpine range of Mount Hood, in North West America; and according to' 

 Zoorey and Gray, Mr. Nuttall found it east of the Blue Mountains of Oregan, 

 not in a subalpine situation. 



It is hardy, with tuberous roots similar to those of the common Paeony, but 

 much smaller. It grows little more than a foot high, and flowers in May. It 

 may be increased either by seeds or by division of the root. 



GERANIACEjE. 



Geranium cristatum, Stev. Crest-seeded Geranium. Bot. Mag. t. 3732. 

 This is a very pretty prostrate species of geranium, growing in the Glasgow Botanic 

 Garden, where it was received from St. Petersburg!!. It is a native of Wakari, 



