FERNS. 



49 



the oosphere, and the new plant is formed. This 

 draws its nourishment in the first instance from the 

 prothallium ; but the latter presently disappears, and 

 the young fern begins to put out independent roots. 



Geographical Distribution. — Ferns 

 require shade and a damp atmosphere. 

 They are most abundant in tropical 

 America, where they reach their 

 maximum concentration " amongst the 

 dripping rocks of the higher level of the 

 Andes, the forests of their slopes and 

 ra\dnes, and the dense humid flats that 

 border the innumerable branches of 

 the Amazon, where the sun's rays and 

 the wind never penetrate the recesses 

 of the primeval jungles, and climbers 

 and parasites contest with the leaves 

 of bright flowering trees for the posses- 

 sion of the branches." Mr. Baker, 

 from whose paper on the subject we 

 quote the foregoing passage, sum- 

 marised the distribution of ferns thus : 

 — Tropical America, 950 species (42 per 

 cent, of all known ferns, three out of 

 four not being found elsewhere) ; 

 tropical Asia and Polynesia, 863 

 species, 427 being 

 peculiar; Polynesia, 

 380 species, 150 

 peculiar ; tropical 

 Africa and islands, 

 346 species, 127 

 p)eculiar ; south tem- 

 perate America, 118 

 species, 32 peculiar; 

 temperate South 

 America, 153 species, 

 21 peculiar ; tem- 

 perate North Ame- 

 rica, 114 species, 37 

 peculiar ; temperate 

 Asia, 413 species. 

 This estimate was 

 published some years 

 ago, but it is still 

 approximately cor- 

 rect, considerable 



sally admired for the graceful lightness of their 

 delicate green fronds, which the dark stalks throw 

 into greater prominence ; and so invaluable to the 

 gardener from the profusion with which these fronds 

 are produced. Perhaps no ferns are so 

 much used with cut flowers as the 

 Maidenhairs. Extending widely, as 

 they do, over the tropical and tempe- 

 rate regions of both hemispheres, they 

 find their headquarters in tropical 

 America. About a hundred species of 

 Adiantum are known, and a large 

 number are in cultivation. Of the 

 species requiring stove treatment, one 

 of the most peculiar, although perhaps 

 not of the most beautiful, is A. reni- 

 forme, a native of Madeira and Tene- 

 rifie. This is distinguished at a glance 

 by its simple roimdly kidney-shaped 

 fronds, about two inches across, having 



the sori situated all round the edge ; 

 Fig. 1.— Prothallium of Maiden- , .j.-in s- . • 



hair, seen from below, with the stems are tutted, trom four to six 



young fern attached, p p, inches high. A variety, known as 

 the proth allium (magmfied p ,i -^t 



about tbirty times) ; d, the asarijoUum, comes from the Mauritius ; 

 young fern ; ww its first an aUied species, A. Parishii, is 



and second roots ; li, root- i 



hairs of prothallium. a native of Moulmein and the Malay 



Peninsula : these form a little section 

 of the genus very 

 distinct from the re- 

 maining species. A. 

 trapeziforme is a well 

 known, handsome 

 plant, of wide distri- 

 bution from Mexico 

 to Brazil. It grows 

 from six inches to 

 a foot high, with 

 stout, erect, shining, 

 dark stems, and a 

 very few spreading 

 pinnge, which are 

 trapezif orm in shape, 

 having the numer- 

 ous sori placed 

 round their upper 

 edges. A. lumda- 

 tum has wiry dark 



Fig. 2.— 1, prothallium of Male Fern (natural size); 2, the same, much hrown stems, and 

 additions having, enlarged; 3, autheridium before bursting; 4, antheroid cells escaping slender pinnate 

 T - T from antheridium ; 5, antheroid cell ; 6, antherozoid or spermatozoid ; „ o j-,- . 



however, been made 7_ ^.vohf^^f^r^ium Ca.ii m^oh enlar^ed^. fronds of thin tex- 



to the Madagascar 



fern-flora especially during even that short period. 



Maidenhair Ferns (Adiantum). — Few genera 

 of ferns are more popular than this, including as it 

 does the various forms of Maidenhair; so univer- 



ture, a foot, or often 

 less, in length. These are frequently elongated at 

 the apex, and take root, as is also the case with 

 the allied A. caudatnm, which is very much like 

 A. hmulatimi, but of a leatheiy texture. A. lunu- 

 latum is widely diffused in both the Old and 



