LYMAN: STUDIES OF HYMENOMYCETES. 
191 
but in the opinion of the writer this resemblance is a chance occurrence 
and cannot indicate any close relationship, since the method of devel¬ 
opment is totally different in the two cases. In Secotium, which most 
closely resembles Lentodium in external appearance and in structure 
of the mature fructification, the plates of the gleba originate by the 
differentiation of internal tissue, and are covered by the thick peridium 
until maturity, when the latter tears away from the stipe below and 
the gleba becomes exposed. Rhopalogaster ( Cauloglossum ) trans- 
versarium (Bose) Johnston, also strongly resembles Lentodium in 
its porose-cellular gleba covered by a thin delicate peridium which 
at maturity becomes pulled apart in many places so as to expose the 
chambers within; but Johnston (’02) found that the original hyphal 
upgrowth from the mycelium becomes differentiated into a cortical 
layer (the peridium) and a medullary portion from which the gleba 
develops. In these species the development is angiocarpic, the 
hymenium arising from internal tissue. On the contrary Lentodium 
is gymnocarpic, since the hymenial plates arise from the superficial 
tissue of the young fructification and are not covered by a peridium 
at any stage of their development; the cottony veil of Lentodium 
being merely an outgrowth of the trama, is not in any sense homologous 
with the peridium of Gasteromycetes. Hence the method of develop¬ 
ment of this fungus definitely excludes it from the latter group and 
allies it with the Hymenomycetes. 
Nor can we place this fungus among the veiled Boleti or agarics. 
The hemiangiocarpic Hymenomycetes which possess a velum uni¬ 
versale, as Amanita, can be more exactly liomologized with the Gas¬ 
teromycetes than can Lentodium, the veil which envelops the young 
egg being compared with the peridium. Nor is the velum partiale of 
Agaricus, Cortinarius, etc., homologous with the veil of Lentodium. 
This structure originates, according to de Bary (’87, p. 290), as a 
hyphal outgrowth from the superficial layers of the stipe and the mar¬ 
gin of the young pileus; these hyphae unite in a close weft which 
bridges across and closes the furrow between the stipe and the forming 
pileus, and is torn in the final expansion of the latter. Hence the 
origin of the veil is quite distinct from that of the hymenial region. 
On the contrary the veil of Lentodium is formed from interlacing 
elements of the trama, has the same structure as the latter, and is 
inseparable from it at all times. Such a growth does not constitute 
a true membrane, as does the veil in Cortinarius and Agaricus, and 
