FILICINEM. 
421 
Order II. Filices^ 
The Sexual Generation (Oophore) or Prothallium of Ferns is a thalloid body 
containing chlorophyll and obtaining its nourishment independently; its development 
presents striking resemblances to that of the simpler Hepaticse, and to a certain 
extent even to the formation of the protoneraa of some Mosses. It produces simple 
tubular unarticulated root-hairs, and finally antheridia and archegonia. Its develop- 
ment and the duration of its life may embrace a considerable space of time, espe- 
cially when the archegonia are not fertilised. 
When the spores germinate, which usually does not take place till a con- 
siderable time after dissemination (but in Osmunda after only a few days), the cuti- 
cularised exospore, generally provided with ridges, bosses, spines, or granulations, 
spHts along its edges ; the endospore, which now protrudes and is not unfrequently 
already divided by septa, produces the prothallium, either immediately, as in 
Osmunda^ or after the preliminary formation of a filamentous protonema, which 
presents in Hymenophyllaceae certain resemblances to that of the Andreseaceae and 
of Tetraphis among Mosses. The development of the prothallium has been more 
exactly investigated only in the Hymenophyllaceae, the Polypodiacese, and also in 
Osmunda and Aneimia'^ ; and the considerable differences which have thus been 
established necessitate separate descriptions. 
In the Hymenophyllaceae the contents of the spore are divided, even before 
germination, into three cells meeting in the centre ; in some species of Trichomanes 
small cells are cut off at three points of the circumference, while a large central 
H. von Mohl, Ueber den Bau des Stammes der Baumfarne (Verm. Schriften, p. 108). — Hof- 
meister, Ueber Entwickelung und Bau der Vegetationsorgane der Farne (Abhandlungen der königl. 
Sachs. Gesells. der Wissen. 1857, vol. V). — Ditto, Ueber die Verzweigung der Farne (Jahrb. für 
wissen. Bot. vol. III. p. 278). — Mettenius, Filices Hort. Bot« Lipsiensis (Leipzig 1856). — Ditto, Ueber 
die Hymenophyllaceen (Abhandlungen der königl. Sachs. Ges. der Wissen, 1864, vol. Vllj. — Wigand, 
Botanische Untersuchungen (Braunschweig 1854). — [On the Germination, Development, and Fruc- 
tification of the Higher Cryptogamia, &c. Ray Society, 1862, pp. 128-266.] — Dippel, Ueber den 
Bau der Fibrovssalstränge, in the Berichte deutscher Naturforscher u. Aerzte in Glessen, 1865, 
p. 142. — Reess, Entwickelung des Polypodiaceensporangiums (Jahrb. für wissen. Bot. 1866, vol. V. 
p. 5). — Leszczyc-Suminski, Zur Entwickelungsgeschichte der Farnkräuter, 1848. — Strasburger, 
Befruchtung der Farnkräuter (Jahrb. für wissen. Bot. 1869, vol. VII. p. 390). — Kny, Ueber 
Entwickelung des Prothalliums und der Geschlechtsorgane, in the Sitzungsberichte der Gesellschaft 
naturforschender Freunde in Berlin, Jan. 21 and Nov. 17, 1868. — Kny, Ueber Bau und Entwickelung 
des Farnantheridiums (Monatsberichte der kais. Akad. der Wissen. Berlin, May 1869). — Kny, 
Beiträge zur Entwickelungsgeschichte der Farnkräuter (Jahrb. für wissen. Bot. vol. VII. p. i).— 
Russow, Vergl. Unters. Petersburg 1872. — Janczewski, Ueber die Archegonien. Bot. Zeit. 1872, p. 
418. — [On the development of the prothallium, see also Bauke, Keimungsgeschiche der Schizaeaceen, 
Jahrb. f. wiss. Bot. XI ; Burck, Develop, du prothalle des Aneimia, Arch. Neerlandaises, X ; Bauke, 
Entwick. d. Prothalliums bei den Cyatheaceen, Jahrb. f. wiss. Bot. X ; Goebel, Entwick. d. Prothal- 
liums von Gymjio gramme lepiophylla. Bot. Zeit. 1877; Janczewski et Rostafinski, Le prothalle de 
V Hymenophyllum Tunbridgense, Mem. soc. nat. d. sei. natur. de Cherbourg, XIX ; Prantl, Die 
Hymenophyllaceen, 1875.] 
^ Although the Osmundacese, Schizaaceoe, and Gleicheuiacese probably constitute a group apart 
from the Polypodiacese and Hymenophyllaceae, I introduce here what little is known concerning them, 
for our knowledge is not sufficient to permit of any but an imperfect account of them being given. 
Where it is not expressly stated to be otherwise, the descriptions given above refer to the Polypodiaceae 
and Cyatheaceee. 
