(254) 
affect our estimate of the value of the anomaly derivable from the higher 
tribes. 
Thelocarpon coccophorum (Mont.) Nyl., to which the former writer 
attributed a foliaceous thallus, associating the plant with Physcia, and 
quadrilocular spores, is defined by Nylander (Pyrenoc. p. 10) who at first 
took it for a Lecanora, as crustaceous, and the spores as simple. If really 
associable with the present tribe, and with the other Thelocarpa, the 
Segestriine character of the lichen cannot well be doubted; in which 
case its ‘lobulate, radiant’ thallus will distinguish it as the analogue here 
of the effigurate groups in the Hulecanorei. In the other known species 
of Thelocarpon, Nyl. (Spheropsis, Flot. in Bot. Zeit. 1847, p. 65. The- 
lomphale, Koerb. Parerg. p. 321) the instructive descriptions appear to 
indicate a close affinity to Segestria ; as Fries, as above taken, understood 
it. Should this be made out (and Dr. Stizenberger, J. c., has already 
united Thelocarpon and Thelopsis) the spore-character of Segestria will 
only require a similar modification to that which #. Guepini makes neces- 
sary in the character of Endocarpon. 'The spores of these species are 
defined as ‘for the most part uni-septate’ (Nyl.) or ‘ obsoletely bilocular’ 
(Koerb.) and are contained in polysporous thekes. 
Of the two rock-lichens referred to Segestria by Fries, one (S. thelostoma 
—the type of Thelochroa, Mass.? Koerb.?) has since proved (Leight. Brit. 
Ang. Lich. p. 34, t. 15, f. 2) to be sharply distinguished from the other by 
its simple spores. According to the views maintained in the present 
work, simple spores may characterize species of any genus; and they 
afford thus no ground for rejecting the other evidence of affinity connect- 
ing S. thelostoma with S. lectissima. It is interesting, taken in connexion 
with the described lecanoroid features of Thelocarpon coccophorum, Nyl., 
and with the well-marked, tartareous thallus of S. thelostoma, that both 
Smith and Hooker regarded the latter as better associable with Lecanora ; 
while even Leighton suggests (J. c.) that ‘it may be improperly placed 
among the Angiocarpi.’ 
Segestrella, Koerb. Syst., the type of which is S. lectissima, Fr., is also 
dignified, in Segestria mammillosa, Th. Fr., by a ‘thick, intricately ramu- 
lose-torulose’ thallus; and the quadrilocular spores become finally, in 
S. Ahlesiana, Koerb., plurilocular. 
Geisleria, Nitschke (Rabenh. Lich. Hur.n. 574. Koerb. Parerg. p. 326) 
an earth-lichen found as yet only in Westphalia, and regarded by its dis- 
coverer and by Koerber as especially distinguishable from Sychnogonia 
(Thelopsis, Nyl.) by its octosporous spore sacks, is perhaps as readily 
associable with Segestrella ; and is in this connexion interesting, as its 
spores, though very commonly quadrilocular (‘normaliter tetrablaste,’ 
Koerb. l. c.) tend at length (Nitschke l. c., and I have made the same 
observation) to a sub-muriform interior configuration ; suggesting that 
the lichen, and the group to which it shall prove to belong, is possibly, 
after all, as regards its spore-character, a decolorate exhibition of the 
