Rœstelia cancellata, Reb. Pear-leaf Rœstelia; spots yellow, then red, prominent; peridia split to the base into laciniæ, which remain united at the apex.—On Pear leaves. Not very common. Autumn. ([Plate II.] figs. 20, 21.)
Rœstelia cornuta, Tul. Horn-like Rœstelia; spots rusty-brown; peridia cylindrical, slightly curved, yellowish-brown; spores greyish, at length brown.—On the under surface of the leaves of Mountain-Ash. Not common. August. ([Plate II.] figs. 18, 19.)
Rœstelia lacerata, Tul. Lacerated Rœstelia; peridia clustered in tufts, brown, elongated, splitting to the base in segments; spores light brown.—On the under surface of the leaves, and on the petioles and fruit of the Hawthorn. Not uncommon. May to July. ([Plate II.] figs. 22, 26.)
Peridermium, Chev.
Peridium elongated, at length bursting irregularly. Spermogonia scattered, conspicuous.
Peridermium Pini, Chev.; peridia oblong, scattered, large; spores orange, abundant; spermogonia vernal or autumnal, or both; spermatia large, white.—On leaves and young branches of Scotch Fir. Common in Scotland, occasional in England. Summer. ([Plate II.] figs. 27, 28.)
Peridermium elatinum, Lk.; simple, immersed; peridia elliptic, pallid; sporidia orange.—On Silver Fir, altering both foliage and ramification. Not common.
Æcidium, Pers.
Peridium seldom elongated, opening by a terminal mouth, surrounded by a fringe of recurved teeth, or when short bursting irregularly. Spores disposed in chains. Spermogonia on the same or the opposite surface, clustered or scattered, central or intermixed.
Sect. I.—Peridia scattered (not collected in tufts or clusters).