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Sub-Fam. 1. — LICHINEI. 
Thallus fruticulosus filamentosusve, collogonidiis aut axem, de- 
mum dissolutum, sistentibus, aut in stratum sub-stipatis. Medulla 
plus minus parenchymatica. Apothecia globosa varie deformatave 
1. pseudo biatorina. 
It might perhaps be beforehand conceivable that constriction should 
so modify Collemeine structure as to give, in at least extreme types, a 
peculiar prominence to the everywhere sufficiently marked gonimous sys- 
tem ;—and we find, in the younger portions of Hphebe (Hepp. Abbild. t. 
81, n. 712) and its nearest associates (Ibid. t. 82, n. 713) the collogonidia 
constituting the axis, and almost the plant. Ccnogonium, Ebrenb., as 
Nylander has explained it, is perhaps a still more simple, gonidial thallus: 
but here chlorophyll, conditioning true gonidia, appears ; and the type is 
thus excluded from the Collemei; as it is also by the ensemble of its fruc- 
tification. There are analogous instances in the present and other tribes 
of a marked predominance of the medullary layer; and yet again of the 
disappearance of this layer in a general parenchymatous tissue; and if 
neither of these extremes of reduction or simplification should be taken 
to be enough to exclude the plants exhibiting them from that place in the 
system to which the sum of their characters points, it will be difficult to 
adopt another rule in the case of those which are extraordinarily condi- 
tioned by the gonidial element. 
External habit proved an uncertain guide to the real affinity of the 
plants now immediately before us, so long as their fruit-characters were 
unknown or undetermined; and structure itself was long looked to in 
vain —the significance of the fructification being disputed —to distin- 
guish some of them from (inferior) Alg@, which seem scarcely to differ 
but in failing always to ascend above an inferior stage of life. It is how- 
ever the ennobled Stigonema (Ephebe) that should throw light on the rest 
of its group; and though the probability (Koerb. Parerg. p. 448) remain, 
that, taken as a whole, these humble types may continue in bivio,—a 
part being always referable, from the point of view of system, to Alga, this 
cannot embarrass those whose place is otherwise determined; or the argu- 
ment from them to the undetermined remainder. And keeping in view 
the essentially mediate character of the class we are here studying (Lich- 
enes quoad vegetationem ad Algas relatos, quoad fructum Fungos esse, Fr. 
S. O. V. p. 60) it may well appear possible to accept all the evidence 
indicative of points of contact between Parmeliaceous Lichens and Alga, 
without greater embarrassment or need of modification of the higher 
divisions of Thallophyta, than are offered or suggested by the close and 
often difficult relations between Graphidaceous and Verrucariaceous types 
and Fungi. 
Nor has habit wholly failed to indicate or corroborate the received 
