88 MR. C. B. PLOWRIGHT ON CERTAIN 
Experimental Observations on certain Brig Hetercecious 
Uredines. By Cmarres B. PLowrıdar, F.L.S. 
[Read 5th May, 1887.] 
Puccınıa PHALARIDIS, n. sp.; soris minutis, punctatis, vel 
linearibus, nigris, epidermide tectis; sporis levibus, brunneis, 
sessilibus vel perbreviter pedicellatis, quadratis vel infra attenu- 
atis, truncatis vel supra conglobatis, interdum oblique capitatis, 
pavlulum constrictis. 
I. ZEcidiospores.—Cups mostly hypophyllous, in circular 
clusters on yellowish spots, not very prominent, with whitish, 
rather torn edges. Spermogonia appearing first upon the upper 
surface of the leaf centrally, then surrounded by the cups. 
Spores roundish, yellow, 20 to 25 mk. 
II. Uredospores.—Sori orange, elongated, oval, oblong, or 
linear, small, sometimes confluent, at length naked. Spores sub- 
globose or oval, orange-yellow, echinulate, 20 to 25 mk. 
III. Teleutospores.—Sori minute, punctate, or linear, black, 
covered by the epidermis. Spores smooth, brown, sessile, or 
with very short pedicels, quadrate or attenuate below, truncate 
or rounded above, sometimes obliquely capitate, slightly con- 
stricted. The spores are surrounded by a bed of dark brown 
tissue, the individual fibres of which are not easily demonstrable ; 
40 to 50 mk. long, by 15 to 18 mk. wide. 
I. Zeidium Ari, Desmaz. Catal. des Plantes omiss. 1823, p. 26 ; 
Cooke, Handb. p. 545. On Arum maculatum, L. 
II. and III. On Phalaris arundinacea, L. 
One of the more uncommon of our British Uredines is the Zei- 
dium which occurs in spring and early summer upon Arum macu- 
latum. This is the more striking because, not only is the host plant 
abundant, but also from the nature of its foliage and the manner of 
growth of the Zeidium ; the latter, when it does occur, is very con- 
spicuous, and hence unlikely to be overlooked. It is accompanied 
by no other spore-form upon the Arum, and is regarded as an he- 
terccious species, the affinities of which are unknown. During 
the months of May and June, 1884, I was fortunate enough to meet 
with this Zeidium in a lane at Gayton, near King's Lynn. This 
lane is about two miles long, and on both sides of it the Arum 
was growing in abundance; but in one spot, and in one spot only, 
extending for not more than a dozen yards, could the Zeidium 
be found. Repeated visits to the spot, and a careful examination 
of the Grasses and Carices in its immediate vicinity, led to the 
