NEW AND RARE PLANTS. 
209 
portion of cultivated ground would have long since become a barren waste, and the 
most essential and valuable vegetable productions of the earth would now be 
unknown. 
The practice of burning soils or subjecting them to the action of intense heat, 
has been recommended by some for destroying extraneous matters ; but however 
useful this may be with clayey earth, to promote pulverization, we cannot think it 
worthy of adoption for the purpose here alluded to ; and we would recommend 
exposure to the air as one of the most simple, and at the same time the most 
efficacious, method of regenerating all soils that are impregnated with the rejections 
of plants. Our objects in these remarks has been to place the most prominent 
parts of this subject before our readers in their true light, with their practical 
consequences and suggestions ; and as our limits have not permitted us to enter so 
minutely into the consideration of it as it deserves, we shall perhaps revert to it 
at some future opportunity ; we now leave it to the candid attention and investiga- 
tion of the reader, convinced that a knowledge of it is of the utmost importance to 
the practical cultivator. 
NEW AND RARE PLANTS, 
FIGURED IN THE LEADING BOTANICAL PERIODICALS FOR SEPTEMBER. 
CLASS I.— PLANTS WITH TWO COTYLEDONS (DICOTYLEDONE^). 
THE MELASTOMA TRIBE {Melastomacets). 
Arthrostemma VERSICOLOR. Cliangeable-flowered Arthrostemma. A most 
interesting little half-shrubby stove plant, recently raised in the Glasgow Botanic 
Garden, from seeds sent there by Mr. Tweedie, but had previously been discovered 
by Mr. M'Rae, collector to the Horticultural Society, at St. Catharine, on the 
eastern coast of Brazil. It bears a great number of pretty pink blossoms from the 
extremities of the shoots ; they are produced in the months of July and August, 
and render it very ornamental. It is the Rhexia versicolor of Dr. Lindley. 
Bof. Mag. 3678. 
THE ROSE TRIBE {Rosacece). 
Potentilla glabra. Glabrous Potentilla. This is by no means a showy, 
although a shrubby species of the genus. It is dwarf, entirely smooth, and the 
branches incline downwards, producing their neat yellowish-white flowers at their 
extremities. Being quite hardy, it is said to form an interesting feature among 
the various species of Cistiis, where these are cultivated collectively. Siberia is its 
native country, and it was first imported by Messrs. Loddiges, who state in the 
Botanical Cabinet that it is somewhat difficult of propagation. We presume it 
may be increased by layers. Bot. Mag. 3676. 
VOL. V. — no. lvii. e e 
