176 
THE FLORIST’S JOURNAL. 
By attention to these rules, in which it appears that a high 
temperature, combined with great humidity, are the essential 
points, and some amount of practical tact, success may be re¬ 
garded as nearly certain. 
The genus contains, besides those mentioned, seven other 
species, all of them ornamental, though but seldom met with, 
which may be accounted for by the acknowledged difficulty 
hitherto experienced in preserving them through our long and 
often severe winters. They are chiefly natives of the West 
India Islands, and of South America, the home of many of our 
most beautiful plants. Lisianthus is derived from lysis, dis¬ 
solution, and anthos, a flower, in allusion to its being a powerful 
cathartic. It is included in the natural order Gentiancicece 
and in the Linneean arrangement will be found in Class 5. 
Order 1. 
Editor. 
Horticultural Essays, 
By the Members of the Regent's Park Gardeners' Society. 
VEGETABLE PHYSIOLOGY. — THE LEAVES OF 
PLANTS. 
By Mr. T. Moore. 
(Continued from page 168.) 
Ti-ie anatomical structure of a leaf, therefore, is this: from 
the medullary sheath a bundle of woody tissue diverges, accom¬ 
panied by spiral vessels, and passing through the bark produces 
numerous ramifications, forming a kind of network. At that 
point of the stem where this matter issues, the cellular matter 
of the bark diverges also, and becomes expanded with the 
ramifications of the fibro-vascular tissue. This latter having 
proceeded to the extremity of the leaf doubles back and returns 
beneath, forming a separate layer of fibre, which, converging 
with the stem, finally connects itself with the liber ; the upper 
layer of network is, therefore, in connection with the medullary 
sheath, and the lower with the liber. The remaining portion of 
the leaves is parenchyma, enveloping these vessels, and the 
