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XXX. Observations on the Structure and Development of the Organs of 
Pilularia globulifera. / Jn a Letter to R. H. Sorry, Esq., F.R.S. & L.S. 
By WIILLIAu VALENTINE, Esq., F.L.S, 
Read March 19th, 1839. 
FROM various causes, particularly removing from North Wales to this 
place, I have not had it in my power at an earlier period to reduce my 
observations into proper form for your perusal. A visit to St. David's would 
amply repay a botanist, as, from what I saw, I conceive it to be a rich 
locality, and, as far as I know, not yet explored; but having on the second 
day of my arrival'gathered Pilularia globulifera for the first time in my life, 
I determined to bestow all the time I could command on its examination, 
and therefore I did not collect many species. I must beg to remark, that as I 
only know what preceding observers have discovered of the structure of Pilu- 
laria through Lindley's Introduction to the Natural System, and Hooker's 
British Flora, it is possible that the greater part of my observations may be 
already known ; and therefore I leave you to judge whether this letter con- 
tains sufficient novelty to justify its publication. 
The involucrum (Tas. XXXIV. fig. 2.) of Pilularia globulifera contains two 
kinds of bodies, which, however, occupy distinct sacs: one kind (Tas. XXXV. 
fig. 36.) are round, very numerous, and minute, not larger than the 460th part 
of an inch ; they are found principally in the upper part of the involucrum, and 
are about forty in each sac: the other kind (Tas. XXXIV. fig. 3.) are of an 
oblong pyriform shape, a little constricted near the middle, with a conical 
projection at one extremity, and are much less numerous, about sixty, and 
occur singly in each sac; they are about the 80th of an inch broad, and bave 
the power of germination, which the former kind do not appear to possess. 
Both kinds are loose in their sacs, and have an opake, pure white, minutely 
granular, testaceous covering, and are imbedded in a kind of gelatine, which 
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