A sorus or fruit- 

 dot of a Fern. 



FERN 



greater number of genera, ranging from 150 to 250, or 

 even more. In the very unequal treatment by Diels 

 in Die Natiirlichen Pflanzenfamilien (Engler- Prantl), 

 some 120 genera are recognized. A somewhat similar 

 difference prevails in regard to the number of species. 

 The Synopsis Filicum of Hooker 

 and Baker(1874), supplemented 

 by Baker's New Ferris (1892), 

 recognizes some 2,700 species. 

 It is the too common tendency 

 in this work (1) to fail to rec- 

 ognize many valid species which 

 have been described by German 

 and French botanists, and (2) 

 to mass under one name very 

 diverse groups of species from 

 distant quarters of the world 

 from 8 to 10 species not infre- 

 quently appearing as a single 

 so-called "variable species." 

 When we add to the number represented by these 

 two omissions the species recently described, the num- 

 ber of Ferns will approximate 4,000, and possibly exceed 

 that number. New forms are constantly coming in from 

 the less explored parts of the world, and within the 

 last few years several new species have been described 

 fro;n the United States, including some from the bet- 

 ter known portions. Of this number some 200 species 

 are in occasional cultivation in America, but the spe- 

 cies that form the bulk of the Fern trade do not exceed 

 two dozen. In Europe several hundred species have 

 long been in cultivation. Most of the species thrive best 

 in the insular regions of the trop- 

 ics, the island of Jamaica alone 

 furnishing 500 species and Java 

 nearly 600. About 165 species 

 are native in the United States, 

 representing some 35 genera ; our 

 native species are so widely dis- 

 tributed that not more than 

 crom 25 to 50 will be found with- 

 n the limits of one state, and 

 ,he common species of the best 

 ocality do not number more 

 ;han 20. 



The Ferns belong to a group of 

 spore-bearing plants, with vascu- 

 ar (woody) tissue in stem and 

 eaves; this group is technically 

 cnown as the Pteridophytes, and 

 s composed of three orders; viz., 

 he Equisetales, including the 

 torsetails and scouring rushes; 

 he Lycopodiales, including the 

 elaginellas and the club mosses, 

 r ground pines ; and the Fili- 

 ales, including the true Ferns and 

 heir nearer allies. 

 The families of the order Filicales may be distin- 

 uished as follows: 



809. Prothallus of a 



Fern, -with a young 



frond arising. 



A. Spores of one sort (isosporous). 



B. Sporangia with no ring, rising from the interior 

 tissues of the leaf. (JSusporangiate Ferns.) 



1. Ophioglossaceae. ADDER'S-TONGUE FERNS. Prothal- 

 um subterranean, without chlorophyl ; sporangia borne 

 i spikes or panicles on branches distinct from the 

 jliage leaves. 



2. Marattiaceae. Coarse Ferns with sporangia on the 

 nder surface of the leaf, arranged in circular or boat- 

 aaped receptacles : prothallium above ground, green. 



B. Sporangia rising from an epidermal cell, with an 

 elastic ring of peculiar cells, which assist in 

 scattering the spores by rupturing. (Leptospo- 

 rangiate Ferns.) 



c. Leaves filmy. 



3. Hymenophyllaceae. FILMY FERNS. Sporangia at- 

 oned to a thread-like receptacle arising in a cup at the 

 id of the leaf: ring complete, horizontal or oblique. 



FERN 573 



CO. Leaves more firm, herbaceous or leathery. 



D. Ming incomplete or rudimentary: sporangia in 



panicles. 



4. Osmundaceae. FLOWERING FERNS. Coarse swamp 

 Ferns developing copious green spores early in the 

 season: sporangia in panicles at the apex or middle of 

 the leaf. 



DD. Ring apical : sporangia usually single under a 

 scale, or in panicles. 



5. Schizaeaceae. Upright or climbing Ferns with ovate 

 sporangia, which open vertically. 



DDD. Sporangia, sessile, either single or united in 

 clusters of 3-6. 



6. Gleicheniaceae. Terrestrial Ferns with firm texture 

 and usually dichotomous leaves : sporangia opening 

 vertically, in clusters of 3-6. 



7. Ceratopteridaceae. Aquatic Ferns with succulent 

 foliage: sporangia scattered, with a broad ring: leaves 

 of two sorts, the sterile floating. 



DDDD. Sporangia numerous, collected in definite clus- 

 ters (sori). 



8. Cyatheaceae. Mostly tree Ferns with sessile or 

 short-stalked sporangia in conspicuous receptacles, 

 opening obliquely (Fig. 632). 



9. Polypodiaceae. Ferns with stalked sporangia (Fig. 

 807), which burst transversely: sori covered with a 

 membranous indusium or sometimes naked. This 

 family contains five-sixths of all the Ferns. 



AA. Spores of two sorts: minute microspores and con- 

 spicuous macrospores. (Heterosporous.) These 

 spores develop into two sorts of prothalli, the mi- 

 crospores developing only antherids, and the mac- 

 rospores only archegones. 



10. Marsiliaceae. Small plants rooting in mud, the 

 leaves either quadrifoliate or reduced to mere filamen- 

 tous petioles : sporangia borne in oval conceptacles. 

 Often aquatic, with the leaves floating on the surface of 

 water in pools or lakes. 



11. Salviniaceae. Small or minute plants with the 

 aspect of liver-worts, floating on the surface of pools: 

 sporangia in mostly spherical conceptacles. 



The literature on the Ferns is very extensive, since 

 they have ever been attractive plants in cultivation. 

 Many of the species have been illustrated in elaborate 

 treatises by Schkuhr, Kunze, Hooker, Greville, Blume, 

 Fe"e, Mettenius, Moore, and others. Our native species 

 have been illustrated in the two quarto volumes of D. C. 

 Eaton, "The Ferns of North America." A valuable sum- 

 mary of the more common Fern species is found in Dr. 

 Christ's "Die Farnkrauter der Erde" (1897), and the most 

 recent structural and morphological treatment is by 

 Sadebeck, in E ngler- Prantl : "Die Natiirlichen Pflan- 

 zenfamilien." Schneider's "Book of Choice Ferns " is the 

 most complete treatise on the species under cultiva- 

 tion. A useful American horticultural manual is 

 Robinson's "Ferns in their Homes and Ours." 



L. M. UNDERWOOD. 



An excellent little handbook for the wild species of 

 this country is Underwood's "Native Ferns and their 

 Allies." L. H. B. 



GROWING HARDY FERNS. Our hardy Ferns fill a place 

 in our North American flora very worthy of our careful 

 study and admiration. They seem to require so 

 little care, and yet give such general satisfaction, and 

 there is such a variety suited to every taste and con- 

 ditionthat no one need do without them. About 20 

 useful native kinds are evergreen, including the Ore- 

 gon Cliff-brake and Cheilanthes vestlta of the southern 

 states. They are very easy of culture in our New Eng- 

 land climate. About 20, like the Maidenhair, that die 

 down through the winter but have perennial roots, are 

 also easy to grow. In the general cultivation of these 

 hardy Ferns, plant them in a moist, shady situation, 

 with good drainage, and with about one-third leaf -mold. 

 Go to nature in selecting the Ferns. Yet it is a fact 

 that some of these Ferns, like Woodwardia Virginica, 

 found growing so common in wet swamps, will thrive 



