32 A. Henfrey on the Higher Cryptogamous Plants. 
The development of the spores and the germination of the 
larger kind in Piludaria appear to have been first accurately de+ 
Mr. Valentine,* in a paper read before the Linnean 
Society in March, 1839. It is unnecessary to enter into the par- 
ticulars of this paper, which gives accurate statements in most 
points, and mentions for the first time the occurrence of the cellu- 
lar papilla upon the pro-embryo which has since been regarded 
as the “ovule,” analogous to that found on the pro-embryo of the 
other vascular Cryptogams. 1a 
Dr. C. Miiller’st essay appeared in 1840, and agrees in some 
points; but he appears to have mistaken the mode of origin of 
the pro-embryo, In 1843, Schleident announced that he had 
observed a process of impregnation in Péludaria, in which the 
small spores acted the part of pollen-grains, producing tubes which 
entered into a cavity on the surface of the large spore or “ ovule,” 
aud, in accordance with his views of impregnation in general, 
became the embryo. igewe B 3 ot ef 
-- The next paper on the subject was an essay published by Dr. 
Mettenius$ in 1846, in which the anatomy and development of 
Saivinia is treated at length; that of Pilularia and Marsilea less 
perfectly. He did not observe the process of impregnation de- 
scribed by Schleiden, yet from the want of organic continuity 
between the embryo and the “ovule,” he inclined to adopt the 
‘heory of fertilization propounded by Schleiden, both for the 
Phanerogamia and the Rhizocarpex, namely, that the end of the 
pollen-tube penetrated into the so-called ovule and became the 
embryo; nevertheless he had some doubts, since he conld not 
reconcile the production of ‘pollen-tubes” from the smallspores 
of Salvinia with the facts he had observed, and never saw the 
“tube” penetrate the “ovule” in Palularia. Moar aaa 
In 1846, Prof. Nageli published some new and important obser= 
vations on Pilularia.|| in which he stated that the observations 
of Schleiden were altogether incorrect, and that the bodies whi 
that author had described as three or four “ pollen-tubes,” pro- 
uced by the small spores and adherent to the summit of the 
large spore, were in fact parts of this, constituting a papilliform 
structure, forming a part of the pro-embryo developed by the 
large spore itself. Moreover he discovered a totally unexpected 
fact in regard to the small spore or “pollen grains.” He found 
that these, without coming in contact with the large spores at all, 
became elongated by the inner coat protruding like a short pouch- 
like process through the outer. This contained starch-granules; 
and some he found burst and surrounded by starch-grains exactly 
| sais 
* Linnwan Transactions, vol. xvii, -+ Flora, 1840. 
— der Wiss. Botanik, 1843. 
3eitriige zur Kenntniss der Rhizocarpese. Frankfort, 1846. 
Zeitschrift fiir Wiss. Botanik. Heft 3, 4, 188, a Ae ee 
