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Ach., Fr., known already as occurring in New England, as in Arctic 
America, proves to be common in California (Mr. Bolander). ——L. insw- 
laris, Nyl. (Lich. Par. n.58. Herb. Th. Fr. Lecidella, Koerb.) a well- 
marked lichen, with brown, warted thallus, and very minute fruit, has 
occurred, growing, in little patches, with Buellia geographica on the 
Oakland hills in California (Mr. Bolander) and with little doubt is to 
be detected elsewhere. L. tenebrosa, Flot. (Zw. exs.n. 134. Fr. Lich. 
Suec. n. 406, c.) interesting as a lecideine Aspicilia (conf. Koerb, Parerg. 
p. 99) accompanies Buellia geographica in the alpine region of the White 
Mountains; and probably descends. —— L. lugubris, Sommerf., Nyl. (Fr. 
Lich. Suec. n. 351) occurs in the same region with the last; and is well 
marked by its lobulate scales, and globular spores in strap-shaped thekes. 
(Koerb. Syst. t. 1, f. 5). 
Thus far, if we except the effigurate section (Thall@dema) in which 
the spores exhibit an evident tendency to become bDilocular (‘obsolete 
dyblaste, Koerb.) these are reckoned unilocular, and the group (Eulecidea) 
corresponds with the major part of Hulecanora and Hubiatora ; in both 
of which the ‘simple’ spore predominates. But the line of distinction 
between ‘obsoletely bilocular’ or ‘pseudo-bilocular’ and bilocular spores 
is sometimes a difficult one to trace; and Huwlecidea, in as far as we have 
examined it, may well be said to express, in perhaps a different degree, 
the same nisus to pass into bilocular forms that we find in Thalledema. 
This is sometimes (as in L. enteroleuca, v. theioplaca, indicated above, 
and in the v. lutosa, Nyl. (Scher. Helv. n. 579) which last has no claims 
to generical distinction superior to those of the first) so marked indeed, 
that we may well hesitate to call such spores unilocular; and the form last 
named of the just-cited species is in fact referred, by both Koerber and 
Massalongo, to their Catillaria ; the division, in their arrangements, corre- 
sponding, in the group before us, to Biatorina in their Biatorei. Natural 
affinity, as indicated generally, and in particular by the spermatia, appears 
however, as observed by Nylander (Prodr. p. 125) to forbid the separation 
of such forms from the cluster typified by LZ. enteroleuca ;! and, judged 
in the same way, another Catillaria (C. concreta) in which there is no 
doubt of typically bilocular spores, can scarcely berelieved from Nylander’s 
relegation of it (1. ¢. p. 129) to a colourless condition of Buellia atro-alba. 
The bilocular stage in the evolution of the spore, so fully exhibited in the 
second section of Hetherothecium, is in fact suggested, rather than exem- 
1 Scherer’s specimen (Lich. Helv. n. 579) of his ‘ Lecidea lutosa, Montagne! 
in litt.” affords me pseudo-bilocular spores exactly similar to those of the rock- 
forms of L. enteroleuca, to which species Nylander has reduced the former; and I 
have obtained only similar results from Buellia (Catillaria) lutosa, Anz. (Lich. 
Lang. nu. 360). Hepp’s figure of the spores of his Biat. lutosa (Montgn.) vera 
(Flecht. Eur. n. 506) under which Scheerer’s Lecid. lutosa is only cited pro p., 
represents however what appear to be colourless Buellia-spores. Two lichens are 
then, it should appear, currently known under these cited names. 
