British Gastromycetes . 3 
from the earliest period of development exposed to the light ; 
whereas in the genera Stereum and Thelephora a portion of the 
hymenophore becomes free from the substratum and bends 
over, thus turning the hymenium away from the light, and by 
a series of transitions described in detail elsewhere \ we find 
the higher species of the two last-named genera assuming 
umbrella-shaped forms with a central stem and inferior 
hymenium, but not at any period covered by a veil. In the 
Agaricineae we meet with the same sequence of evolution ; in 
such low forms as Cantharellns retirugis , Fr., and Agaricus 
( Pleurotus ) hypnophilus , P., the plants are fixed to the sub- 
stratum by the pileus with the hymenium uppermost, and may 
be compared to a Corticium with the hymenium imperfectly 
broken up into gills, whereas such species as Agaricus (. Pholiota ) 
praecox , P., and Agaricus ( Amanita ) muscarius , L., the hymeno- 
phore is supported on a stem with the hymenium on the 
underside, and concealed by a veil until the spores are mature. 
Finally, the same sequence of sporophore evolution may be 
observed in large genera, as Stereum , Poly poms , and Agaricus . 
There is a marked absence of any special arrangement of the 
sporophore for spore-dissemination. 
In the Gastromycetes, with the exception of the species 
constituting the genus Gauteira , the hymenium is com- 
pletely concealed by a continuous wall or peridiutn until 
the spores are mature. It has been shown that in the 
genera Crucibulum 2 , Phallus* , Sphaerobolus 4 , and Matula 5 , 
the sporophore originates from the vegetative mycelium as 
a minute undifferentiated weft of hyphae, and as suggested 
by De Bary 6 , this mode of origin is probably common 
to all. No traces of sexual organs have been observed. 
The peculiar form of coalescence between two hyphal cells 
1 G. Massee, A Monograph of the Thelephoreae ; Linn. Soc. Journ., vol. 
xxv, p. 107. 2 De Bary, Fungi, &c., Engl. Ed. p. 319. 
3 De Bary, 1 . c. p. 322. 
4 Ed. Fischer, Zur Entwicklungsgesch. d. Gastromyceten, in Bot. Ztg. 1884 
(Sphaerobolus, Mitremyces). 
5 G. Massee, On the type of a new order of Fungi ; Journ. Roy. Micr. Soc., 1888, 
P- 175 - 6 l.c. p. 313. 
