74 Mr Greville on the Genus Erineum. 
and often so confluent as to cover a great part of tlie leaf. Fi- 
laments, or rather tubes, glistening under a pocket lens, and 
bent at an obtuse angle. Under a high power they are cla- 
vate, flaccid and diaphanous, marked occasionally with irregular 
transverse or oblique lines. This is one of our most frequent 
species, and begins to form on the inferior surface of the leaves, 
soon after the tree is in full foliage. 
At Roslin and Braid Hermitage^ it is very luxuriant and 
abundant. 
Erineum tortuosum^ mihi. 
Plate II. Fig. 2. 
E. hypo- et epiphyllum maculaeforme irregulare albo-ferrugi- 
neum^ tubis linearibus cylindricis tortuosis apicibus rotundatis. 
Hah. In foliis Betulae albae ; vere et aestate. 
A beautiful species, white in its young state, and pale or un- 
equally ferruginous when old. Spots irregular^ occasionally on 
the upper as well as the under surface, somewhat tufted, and in 
a slight degree immersed. Tubes, under the microscope, long 
and entangled, linear, flexible, cylindrical, diaphanous, rarely 
incrassated at the apex. This species seems to prefer the young 
and luxuriant leaves which are found in shady situations, on 
the lower branches of young birch trees. It occurs in spring, 
and early in the summer ; and grows at Ravelrig Toll, near 
Currie, among the salices ; and at Bilston Burn, botli in the 
neighbourhood of Edinburgh. 
Erineum tiliaceum, Pers. 
Plate III. Fig. 3. 
E. hypo- et epiphyllum pallidum caespituli sospe eonfluentes, 
tubis linearibus gracilibus apicibus incurvatis. — Gr. 
Erineum tiliaceum, Pers. Syn. Fung. p. 700. 
De Cand. FI. Franc, tom. ii. p. 74.— Syn. FI. Call. p. 15. 
Albert et Seim. p. 370. 
Moug. et Nest No. 98. 
Nees i)on Esenh. p. 64. t. 5. f. 62 . 
Hah. In foliis Tilise europaese ; aestate. 
Always of a pale colour, but in age somewhat yellowish, vei'y 
and distinctive characters. It ought always to be remembered, that, in plants so 
tninute as those under consideration, the microscope can alone be trusted in tracing 
true generic and specific characters. Two plants, whose aspects differ considerably 
before the naked eye, may agree, when magnified, and cannot therefor^ be sepa- 
rated. 
