British Gastromycetes. 25 
cineae and in that of the Polyporeae. From the Polyporeae 
it leads further on to the formation of the Gastromycetes V 
It is important to observe that De Bary admits the in- 
dependent origin of the hymenial portion from internal 
differentiation at two widely separated points in the Basidio- 
mycetes, and further, that the dissimilarity between their 
hymenial apparatus prevents the Gastromycetes from being 
considered as originating from the higher Agaricineae. 
The great objection to De Bary’s view of the origin of 
the Gastromycetes excepting the cases mentioned above, 
which certainly do not appear to be convincing, consists in 
the marked disagreement of every feature considered by De 
Bary as being of greatest importance. As already stated, 
the leading characters of the Hymenogastreae are : sub- 
terranean habit ; homogeneous peridium, remaining intact 
until the spores are mature ; irregularly formed basidia 
bearing a variable number of spores, which are very large, 
coarsely warted or spinulose, and highly coloured. In the 
Polyporeae, all the species grow exposed to light, on the 
ground, or more frequently on decaying wood, and in the 
greater number the hymenium is from the first exposed, being 
protected during the early period by a v£il in only a few of 
the higher forms of Polyporus and Boletus ; the basidia are 
very uniform in shape and constantly tetrasporous, the spores 
being small in size, always smooth, and generally colourless or 
at most very faintly tinged, except in Merulius lacrymans , 
where they are orange- brown, a colour not met with in the 
Hymenogastreae. The broad features presented by the 
two groups respectively, are to my mind diametrically op- 
posed to any idea implying the outgrowth of the one from 
the other. 
It has been already stated that the Hymenogastreae consti- 
tute the starting-point of the Gastromycetes, as was pointed 
out long ago by De Bary, as follows : ‘ That all the groups of 
the Gastromycetes converge towards the Hymenogastreae 
1 1. C. p. 338. 
