QUILLWORT. 
389 
bristle-shaped bars.” Be this as it may, I have preferred in this, 
as in other instances, representing nothing more than 1 have 
seen. Wahlenberg also represents — and other writers have 
adopted his view — the seeds attached to these placentae : this 
also appears to be highly probable, but I have hitherto failed 
in my attempts to prove it correct. The seeds themselves are 
rugose and perfectly white ; they have raised ridges on the 
surface, indicating a quadruple division ; indeed, when thus di- 
vided, the inferior half of each seed is nearly hemispherical, and 
the superior half may be again divided into three sub-triangular 
portions. When crushed, even after the lapse of years, these 
seeds are found to be filled with a transparent and somewhat 
oleaginous fluid. Other capsules contain apparent seeds, which 
are extremely minute, being scarcely equal in size to the pollen- 
granules of many flowering plants : these minute bodies possess 
the form and characters of the larger seeds. The capsules con- 
taining the two kinds of seed are scarcely to be distinguished 
from each other, nor do they follow any law in their relative po- 
sition, as many of our botanists have asserted, but most fre- 
quently occur alternately. Linneus, in his ^ Iter Scanicum,’ 
has described these as male and female flowers,* but botanists 
are not agreed as to their precise nature ; the question, when 
discussed, must comprise the kindred twofold fructification of 
Lycopodium Selaginoides, and probably many other species : 
the real nature of the four portions into which each (supposed) 
seed is divisable, also requires further investigation. 
There are two forms of Isoetes, so different that Dillenius, 
and, in some of his works, even Linneus, treat them as distinct 
species ; thus in the passage quoted from Dillenius, at p. 382, 
they are designated “ Suhularia folio rigido ” and “ Suhularia 
fragilis and in his great work, the ‘ Historia Muscorum,’ the 
same author describes them as ‘‘ The short and thick-leaved 
* Masculi fiores solitarii intra basin foliorura interiorum. Cal. Squama 
cordata, acuta, sessilis. Cor. nulla. Siam. Filamentum nullum. Amliera 
subrotunda, unilocularis, intra basin folii sita. 
Feminei fores solitarii in eadem planta, intra basin foliorura exterioruju. 
Cal. ut in masculis. Cor. nulla. Pist. occultura. Per. Capsnla subovata, 
bilocularis, intra basin folii sita. Sem. nuraerosa, globosa. 
