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OF FILAMENTOUS, FRUTICULOSE, AND FOLIACEOUS LICHENS. 211 
Sprcins 3. P. perforata, Ach., 
Which occurs at the Cape of Good Hope, in America, Polynesia, and Australia. 
Like the preceding, to which I believe it chiefly belongs, it is a most variable 
and puzzling plant. It is non-British, but frequent in warm climates; supposed 
British specimens are all referrible to P. perlata. The examination of a con- 
siderable suite of foreign specimens in the Hookerian Herbarium, named by Ny- 
LANDER himself, convinces me that the majority of foreign, equally with British 
specimens, is referrible to P. perlata, and that the perforate state of the apothecia 
is a most variable and unsatisfactory feature in either P. perforata or P. perlata. 
The normal spermogones of P. perforata would appear to be essentially those of 
P. perlata, being black, punctiform, immersed, and scattered on the flat surface 
of the thallus near its periphery. When degenerate, or aged, they sometimes 
become mere black maculze. In exceptional cases, the apothecia, as in var. 
letiformis of P. perlata, are studded over with spermogones. But the most 
interesting feature in regard to the spermogones is the occurrence, in var. dentz- 
culata, on the margins of the lobes, of enormous barrel-shaped ones which appear 
like a fringe or series of coarse black teeth. Sometimes these occur alone, or as 
the only form of spermogone; at other times, they are associated in the same 
specimen with the ordinary black punctiform spermogones. It is of much 
interest here to notice the double form of spermogone; the fact tends to prove 
that the lichens, as well as the fungi, may have several forms of reproductive 
organs, and that there is nothing more unnatural in supposing the lichens possessed 
of spermogones and pycnides—sometimes of more than one form of each—than 
in allowing that these latter organs are possessed by many fungi, which, for- 
tunately for themselves, have been more fully studied than the lichens! 
Specimen 1.—Long Island, North America, May 1856; Dr A.O. Broptr. The 
apothecia are very large and abundant; they are flat, cracked, or fissured at their 
margins, and have a central lacerate-elongate perforation or fissure. This is 
undoubtedly the P. perforata of authors; but the apothecia and spermogones, 
spores and spermatia, are all those essentially of P. perlata. The spermogones are 
abundant, and, under the lens, distinct; they are scattered about the periphery of 
the thallus. They are minute, round, black spots, or indistinct papillz, having 
their centre pierced by an ostiole, which is generally depressed. The latter is 
round and patent in the older spermogones; it has sometimes a sub-prominent 
black margin, or it may be surrounded by a pale thalline margin, not circum- 
scribed, but passing gradually into the ordinary colour of the thallus. Rarely it 
is seated on a distinct papillar elevation of the thallus. The body of the spermo- 
gone is wholly immersed, and consists of a grayish tissue. The spermatia are 
long delicate needles, about sth long, among the largest and most handsome I 
