HY ALOPSORA 375 
(mostly four) cells; epispore thin, smooth, colourless; germ- 
pore not perceptible. 
On Polypodium Dryopteris. Uredospores, June—August ; 
teleutospores, May and June, on young leaves (Magnus). Rare. 
(Fig. 279.) 
Fischer, who records it also on P. Robertianum, states that the teleuto- 
spores germinate in June. _ Arthur prefers to call the first kind of 
uredospore the ecidiospore; this is possibly correct but, until something 
is known about their development, it is premature to decide. According 
to him, the ecidia have no peridium, and the uredo-sori a very rudimentary 
one, but I have repeatedly found both kinds of spores in the same sorus. 
They appear perfectly smooth, when seen in water. 
DISTRIBUTION : Europe, North America. 
2. Hyalopsora Polypodii Magn. 
Uredo linearis var. Polypodii Pers. Syn. p. 217. 
U. Filicum Desm.; Cooke, Handb. p. 526; Micr. Fung. p. 215 p.p. 
White, Scot. Nat. 1877, iv. 27, pl. 2, f. 7. 
U. Polypodiz DC. Flor. fr. vi. 81. Plowr. Ured. p. 256 p.p. Fungus 
Flor. Yorkshire, p. 204. Sacc. Syll. vii. 857 p.p. 
Pueciniastrum Polypodii Dietel, in Hedwig. 1899, xxxviii. 260. 
Hyalopsora Polypodii Magn. Ber. Deutsch. Bot. Gesell. 1901, xix. 582. 
Fischer, Ured. Schweiz, p. 474, f. 309. Arthur, N. Amer, Flor, 
vii. 112. Dietel, Annal. Mycol. 1911, ix. 530. 
Uredinopsis Polypodii Liro, Uredin. Fennic. 1908, p. 496. 
Uredospores. Sori hypophyllous, minute, scattered, bullate, 
golden-yellow, without a peridium, rup- 
turing irregularly; spores more or less 
globose or ellipsoid, of two kinds, (1) 
thick-walled (2—3 »), with very faint 
warts, 26—38 x 18—29y, with 6—8 
scattered germ-pores, (2) thin-walled _ . 
(1—14 #), covered uniformly with faint ae eee a laces 
distant warts, 22—35 x 13—20 yw, with pee fragilis (Shrews- 
four equatorial germ-pores. 
Teleutospores. In the epidermal cells, often filling them 
completely, showing as yellowish-brown spots on the under side 
of the leaf, densely crowded, divided into 2—4 cells, each about 
14—18 in diam., single cells subglobose; epispore thin, 
colourless; germ-pore perceptible at the upper end. 
