JP 
a 
13 
at all in the seeds of Iris, to which you call my attention, as 
differing from each other in the same way. ‘The difference, 
there, is no more than occurs between Hippeastrum reticula- 
tum and vittatum. Iris seeds have two separable coats. In 
some there is a vacuum or cavity between them ; in fetida 
that cavity is filled with pulp, and in others it is more or less 
filled, but the inner coated kernel is alike in all; and the 
difference is merely the absorption of the intermediate pulp. 
The outer coat of the seed of Iris foetida is easy separable 
from the pulp.” 
CLESTINES. 
Professor Morren has given this name to those well-known 
large cells of cellular tissue in which raphides, or acicular 
crystals, are deposited in plants. He finds that in Musa pa- 
radisiaca the clestine is produced among oval tissue of the 
divisions of the air cells in the leaves of that plant, and that 
for a long time after the appearance of crystals in the inside, 
it preserves its oval figure. So long as it remains attached 
by a single point to the cells of this partition it retains that 
form, but by degrees the surrounding tissue alters into acti- 
nenchyma, or starry tissue, and then its adhesion to the cells 
from which it receives its food takes place at several different 
points; whereupon in augmenting in size and gaining a much 
greater capacity than the surrounding actinenchyma, it at- 
taches itself to the rays of the latter by legs or peculiar exten- 
sions, which may amount to the number 8 or 10. But if it 
is formed at the borders of the prismatical tissue of the parti- 
tions, it acquires the form of a cylinder with two beaks. He re- 
gards clestines as analogous to the biforines observed by Turpin 
in a few Araceous plants, but differing in not possessing the 
apertures required for the ejaculation of their contents under 
the influence of endosmosis: Observations sur U Anatomie des 
Musa, in the Bulletin. de Ac. R. de Bruxelles, VÍ. no. 3. 
Recensio specierum generis Pteridis, auctore Jac. G. Agardh, Lunde, 1839, 8vo. 
In a pamphlet of 86 pages Dr. James Agardh has given 
an arrangement, with their specific characters, synonyms, 
and history, of the great and difficult genus Pteris, the species 
of which, after eliminating such as are now referred to other 
genera, amount in number to 94, the distinctions of which 
