6 Pitcher, Remarks on Ferns. [voK xxx. 



I. — Roots. — ^These consist of a mass of delicate fibrous tissues 

 by which the plants are able to extract moisture and 

 nutriment from the soil. They may assume the same 

 form as in ordinary plants, or that of a creeping stem, 

 known as a rhizome, developing roots at various stages. 



2. Stems. — ^These may assume an aborescent habit in the form 



of a trunk, which may increase in height, according to the 

 lengthened continuance of its summit growth, from two to 

 sixty or eighty feet ; or herbaceous habit, on a plan similar 

 to the aborescent kinds, but on a smaller scale ; or the 

 form of a fleshy rhizome. 



3. Fronds. — ^These may be either alternate or in the form of 



a terminal tuft. They consist of a stalk, known as the 

 stipe (or undivided, unbranched portion) or rachis (branched 

 or divided portion), and bearing simple or variously divided 

 or compound laminum, pinnae, or pinnules. When young 

 the fronds of all ferns, except in the case of Ophioglossum, 

 are rolled inward, termed circinate. 



4. Fruit. — This consists of spores contained in a spore-case or 



sporangium, borne, as previously mentioned, in spots or 

 lines or masses in collective clusters or patches known as 

 sori, which, at times, are covered with a thin membrane 

 called the indusium. From spores are developed young 

 ferns. So far as the work of the Great Designer has been 

 able to be interpreted, it is found that at the early stage 

 of the germination of the spore there arises from it a green, 

 leaf -like expansion called a prothallium. This, examined 

 microscopically, reveals, on its under hairy surface, 

 cellular bodies of two distinct kinds, the more numerous 

 rounded ones, called antheridia, and the long, spindle- 

 shaped ones, archegonia, which are equivalent to the 

 stamens and pistils of flowering plants. Subsequently, 

 the young plants arise, apparently from the prothalhum. 



Number and Distribution of Ferns. 



The total number of species of ferns, admitted and described 

 by Messrs. Hooker and Baker in their work, " Synopsis Filicum," 

 published in 1863, was 2,235. C^rl Christensen, in his " Index 

 Filicum," recently published, enumerates 5,950 species, repre- 

 sentative of 149 genera. 



Bentham and Mueller, in the " Flora Austrahensis," recog- 

 nized 38 genera of Australian ferns, of which 29 have a 

 general range over the Old and the Kew World, 5 have a wide 

 distribution over the Old World, 3 are confined to New Zealand 

 and the Pacific islands, while only one genus is endemic— viz., 

 Platyzoma. This genus, which has only one species, P. 

 microphyllnrn, has, however, since been included by Baron von 



