374 HYALOPSORA 
possible alternate hosts. This is in itself improbable and is 
inconsistent with Arthur’s suggestion that pf the two kinds of 
uredospores the first kind represents zcidiospores. 
1. Hyalopsora Aspidiotus Magn. 
Uredo Polypodti Schrét. Krypt. Flor. Schles. iii. 374. Plowr. Ured. 
p. 256 p.p. Sacce. Syll. vii. 857 p.p. 
U. Aspidiotus Peck in Ann. Rep. N. Y. State Mus. xxiv. 88. 
Melampsorella Aspidiotus Magn. Ber. Deutsch. Bot. Gesell. xiii. 288. 
Puceiniastrum Aspidiotus Karsten, Bidr. Finl. Nat. Folk, 1879, xxxi. 
143. 
Hyalopsora Aspidiotus Magn. Ber. Deutsch. Bot. Gesell. 1901, xix. 
582, Arthur, N. Amer. Flor. vii. 112. 
H. Polypodii-Dryopteridis Magn. in Hedwig. 1902, p. 224. Fischer, 
Ured. Schweiz, p. 472, f. 308. 
Uredospores. Sori amphigenous, scattered, small, round, 
up to $mm., golden-yellow, without a peridium, dehiscing 
irregularly, often seated on yellowish spots; spores oblong or 
ellipsoid, of two kinds, (1) thick-walled (24—34 4), with very 
Fig. 279. H. Aspidiotus. Part of frond of P. Dryopteris, showing uredo-sori, 
nat. size ; three spores, all from the same sorus (Scotland). 
faint, hardly perceptible warts, 36—72 x 30—40 p, with 6—8 
scattered germ-pores, (2) thin-walled (about 14,), covered 
uniformly with very faint scattered warts, 283—40 x 16—26 xu, 
with four indistinct equatorial germ-pores ; paraphyses few. 
Teleutospores. In the epidermal cells, often filling them 
completely, roundish or irregular, flattened where they are in 
contact, sometimes arranged in two layers, about 25 u high, 
21—35 w or more wide, divided by vertical septa into 3—5 
