282 TAKEDA—ASIATIC POLYPODIUMS. 
readily distinguish this species from any allied members of this 
genus. 
The frond is perhaps the most polymorphic of its kind, so 
that if extreme forms are compared, they at first glance 
appear as if distinct species. A comparatively small form with 
narrow and pointed fronds, as delineated by Clarke,* was first 
described by himself in 1880 under the name of P. clathratum, 
while a still smaller form with very obtuse frond was described 
by Regel soon afterwards as P. Alberti.t A much larger form 
than Clarke’s type, but similar to it, has been distinguished 
by Blanford as var. jakonense.{ Through the kindness of Dr. 
T. Nakai I have been able to make out that P. Uchiyamae, 
Makino § is also a synonym of P. clathratum. As a matter of 
fact, the dimensions of fronds vary from 3 cm. up to over 30 cm. 
in length (exclusive of the stipe), and 5 mm. to 25 mm. in width. 
The apex may assume any form between roundish-obtuse to 
caudato-acuminate. The stipe is also subject to variation; 
the shortest examined measures 5 mm., while the longest one 
reaches 7 cm. In such circumstances ‘it is quite impossible 
to draw any line between these varieties of shape. There is, 
however, an interesting variety of this species found in Tibet, 
which possesses small fronds more or less shortly three- to five- 
lobed at the base. The writer proposes to ¢all this form var. 
lobatum.|| 
Some forms of this species resemble P. nudum, and others 
are similar in appearance to P. excavatum;: from the former our 
plant can be distinguished by the thin membranaceous frond 
and the clathrate scales, and from the latter by the superficial 
sori and also by the nature of the scales. 
The ripe sporangia are of a bright orange colour, and inter- 
mingled with them are often seen the peculiar black clathrate 
and strongly dentate scales. The sori are oblong or elliptical, 
and are often confluent. 
This species is widely distributed over Turkestan, Afghani- 
stan, Kashmir, Punjab, Nepal, and China. It is very interesting 
to note that it also occurs in the Loochoo Islands and in the 
province of Tosa, in Shikoku, Japan. The following specimens 
from China have been examined :— 
Peking Mountains, shady rocks at oe ft., rare (Hancock, 
* Ferns N. Ind. P- 559 (1880), tab. lxxxii, fi 
7-10 mm. latae, acutae co , basi vi el hastatae vel tri- lanhaabans 
fobatae, lo lobis brevibus, 5-25 mm ae acutis vel og rene Tibet, Lhassa (L. A. 
Waddell, Sept. 1904), Kyi chu Valley, 15 miles east of Lhassa (Walton, Aug. 1904) ; 
Gooring Valley, about 16,500 ft. (Littledale, July 1897). 
