268 TAKEDA—ASIATIC POLYPODIUMS. 
their extreme forms really appear, in some cases, as if distinct 
species. There is, consequently, a great difference of opinion 
amongst botanists as to the specific limit of P. lineare. In addi- 
tion to the fact just mentioned, this species has, from time to 
time, been confounded with other species of a similar appearance, 
especially with P. nudum and vice versa. The confusion in 
nomenclature of the species belonging to this group has been 
further accentuated by the fact that different authors, and in 
some cases even the same botanists, have described the same 
species under several specific names, whilst several species of 
the group have been incorrectly reduced by others. 
The modus operandi of botanists dealing with the plants of 
this group is either to include all the species under the all- 
embracing P. dineare, or to regard each form as a distinct species. 
The latter method more clearly shows, in a flora or a work of 
- similar nature, which species or forms occur in certain districts, 
and is more valuable than the other, which gives us only a 
vague idea of the geographical distribution of this group of ferns. 
The practice of disregarding subordinate forms, which is usually 
adopted, having been handed down to us from the past, does not 
carry one far, and is in every respect at variance with the modern 
conceptions of systematic and geographical botany. 
It is, however, by no means an easy task to clear up all the 
misconceptions and confusions in connexion with P. lineare, 
and to arrange the members of this group. As I have been in the 
fortunate position of examining the type or co-type specimens 
of most of the plants referred to P. lineare by different botanists, 
together with several others described as varieties of or closely 
allied to P. lineare, | propose to systematise all the varieties 
and forms of P. lineare known to me, and to make some remarks 
upon each one of them, together with the allied species. 
Polypodium lineare, Thunb. amplif. 
160% Thunbergianum, (Kaulf.) Takeda. 
Syn. :—P. lineare, Thunb. Fl. Japon. p. 335 (1784); Makino, 
Phan. et Pter. Japon. Ic. Illus. sub tab. ix (1899). 
Pleopeltis Thunbergiana, Kaulf. Wesen d. Farrnkr., p. II 13 
(1827). 
Pl. elongata, Kaulf. Enum. Fil. p. 246 (Bag). 
P. atropunctatum, Gaudich. Freyc. Voy. Bot. p. 346 (1828) ; 
Mett. Polyp. n. 160 (1857); Hook. et Arn. Bot. Beechey’s Voy. 
Pp. 103 (1832). 
_ P. lineare a typicum Makino, in Téky6 Bot. Mag. xv, p. 61 
(Igor). 
Frondes plerumque subcaespitosae vel sparsae, 10-30 cm. 
