DR. LINDSAY ON WEST-GREENLAND LICHENS. 307 
Such parasites are more or less common * in species of the following genera :— Cla- 
donia, Ramalina, Cetraria, Thamnolia, Solorina, Peltigera, Stereocaulon, Parmelia, 
Physcia, Umbilicaria, Squamaria, Placodium, Lecanora, Lecidea, Endocarpon, Ver- 
rucaria. | 
2. More than one form, in the same lichen-species, of apothecia, spermogonia or pyc- 
nidia, or of their contained reproductive corpuscles—sporidia, spermatia, or stylo- 
spores. lllustrations are to be found in Lecanora subfusca, L. tartarea, L. varia, Squa- 
maria chrysoleuca, Dactylia arctica, and Thammolia vermicularis. And I have entered 
more fully on the subject in my paper on “ Polymorphism in the Fructification of 
Lichens" +. 
3. Sterility.—Mere absence of apothecia, spermogonia, or pycnidia }; or their occur- 
rence in an abortive or degenerate form. 
Among the more marked illustrations are the following :—Spherophoron coralloides, 
Thamnolia vermicularis, Usnea melaxantha, Parmelia saxatilis and olivacea, Physcia 
pulverulenta and stellaris, Cetraria islandica, cucullata, and nivalis, and Nephroma 
arcticum. 
4. Deformities of (1.) the reproductive and (IL) the vegetative organs, the various 
results of :— | 
(a) Hypertrophy or atrophy. 
(6) Degeneration or abortion. 
(c) Homologous or heterologous growths. 
These deformities include, in regard to the 
(L) Reproductive system :—various monstrosities of the apothecia, spermogonia, 
or pycnidia, which are illustrated e. y. by the genus Lecanora. 
(IL) Vegetative system :— 
(a) Disproportionate development, e. y. of the horizontal, foliaceous, or squamulose 
thallus in Cladonia, the podetia being absent or dwarfed. 
(b) Clothing of podetia with warts, granules, squamules, or folioles, e. y. in Cladonia 
and Stereocaulon. 
(c) Isidioid and Spherophoroid growths, the former represented by the pseudo- 
genus Isidium, the latter by the var. spherophoroidea of Parmelia saxatilis, 
The development of Jsidia is illustrated by Lecanora glaucoma, tartarea, and 
parella; by L. spodophea, Whinb., a Finmark and Nordland lichen ; and by L. 
aipospila, Whlnb., a Spitsbergen one,—the two latter being figured in our ovn 
‘English Botany’ (t. 2083). The isidioid states of these Lecanore constitute 
pseudo-species of the pseudo-genus Isidium, especially I. corallinum and I. coc- 
codes. Mudd is wrong in referring all British forms of Isidium (save oculatum) 
to species of Pertusaria. Isidium cannot be referred to that genus in Green- 
* Vide * Enumeration of Miero-Lichens Parasitic on other Lichens," Quart. Journal of Microscopical Science, 
January, April, and October, 1869. . : : 3 
t * Report of British Association, 1867, p. 89 ; and * Quart. Journal of Microscopical Science, January, 1868. 
_ + This includes rudimentary conditions, e. y. those constituting the pseudo-genus Lepraria. 
272 
