622 



THE FERN FAMILT. 



years attracted as much interest in them on the part of cultivators 

 and amateurs, as has their fructification and germination on the part 

 of tha physiologist. It has long been known that they can be repro- 

 duced from their spores, but it has only lately been ascertained that 

 these spores when sown are developed into minute, green, leafy expansions, 

 called prothalli, which alone have any analogy to the flowers of other 

 plants. For on the prothallus are produced minute bodies, vchich have 

 been compared to stamens and pistils, from whence the young Fern is sub- 

 sequently developed. The spore may, under this theory, be said to be a 

 young flower-bud, which only opens after it has fallen, the spore-case being 

 an involucre enclosing innumerable buds, and the sorus a whole inflores- 

 cence. 



The Umitation of genera and species in the Ferns has always been a 

 matter of great difficulty, and of late years their spUtting and changing has 

 been carried to such a degree as to throw the whole nomenclature into a 

 state of utter confusion. The best characters are taken from the form and 

 arrangement of the sori and of then- indusium ; and some large genera, such 

 as Adiant, Spleen/wort, etc., are natural, and readUy recognized ; but in 

 Polypody, Shield-Fern, Bladder-Fern, etc., there is notliing in habit to 

 serve as a guide, and the indusium of the two latter genera is often- so 

 evanescent that it requires the most careful examination of specimens, in 

 exactly the proper state, to ascertain its existence. I have been induced, 

 therefore, with a view to assist the beginner in the determmation of the 

 British species, to include in the following Table of Genera the species also 

 of the most difficult ones, endeavom-ing to lead to them by more prominent 

 characters, without reference to the more minute, although essential ones, 

 which distinguish the genera. It must be recollected, however, that to de- 

 termine Ferns they must be in fruit. It is hopeless to attempt to find out 

 by books to what species a barren frond belongs, and monstrous develop- 

 ments, and deformed fronds, now not uncommon in cultivation, and found 

 occasionally wild, are here whoUy passed over.* 



^Fructification in a terminal spike or panicle. The frond either leaf-Uke, or bearing a 

 J J leaf in the lower part , . i . 3 



/ Fructification in a little cup or involucre at the edge of the frond . . . . S '. 4 



^^Fructification on the back or under side of some or aU the fronds . . . . '. . 5 



rFronds twice pinnate, usually 2 or more feet high, the fructification forming a panicle 

 2 -i at their extremity 3. OsiinNr. 



LFronds Btem-Uke, not 6 inches high, with a terminal spike or panicle 3 



g r Spike sunple. Leaf entire 1. Addeb's-tongue. 



I Spike branched into a panicle. Leaf pinnate 2. Moonwoet. 



rFronds numerous, scarcely 2 inches high, pinnate, with few deeply-lobed segments. 



4St? J ''''®''™*®'^''°''^" 17. Hymknophyli,. 



) i ronds 6 or 8 inches high, 2 or 3 times pinnate, with crowded segments. Involucre 



>_, ""P.-shaped 16. Teichomanes. 



ri< ronds tuited, of 2 sorts, the central ones erect, fruiting, the outer ones barren, 

 5.^ usually shorter, with broader lobes ■, . 6 



^Fruiting and barren fronds similar or nearly so .' . .'^ ! 8 



rFronds (stiff) simply pinnate, with entire lobes, the fruiting linear, the barren lance- 

 °) oJate. 11. Blechnum. 



^Q . ?' (dehcate) much divided, with small, obovate or oblong, toothed lobes . . 7 

 yf Son forming a line close to the margin of the frond 5. Allosokus. 



I Son oblong, scattered on the surface of the frond 6. Gymnogbam 



* Further details of this beautiful tribe of plants may be found in the numerous Ulus- 

 trated works on Ferns which are daily advertised, among which Mr. Moore's • Hand- 

 book of British Ferns ' wUl be found a neat and compact, as weU as an accurate aid 

 nseful compendium. i: 



