MR. GEORGE MASSEE ON THE THELEPHORES. 117 
hyphe growing parallel to the substratum, and giving origin 
to numerous erect branches of similar structure, some of which, 
by further branching, form a corymbose head, each terminal 
branchlet developing into a clavate basidium producing four 
spores supported on slender sterigmata. Others of the erect 
branehes at about the level of the base of the basidia develop at 
the apex a stellate arrangement of branchlets, all situated in one 
plane parallel to the surface of the hymenium; the number of 
rays varies from three to seven, five being most frequent, and 
differ from the supporting hyphe in being aseptate, with very 
thick walls which soon become bright brown (Pl. XLVI. figs. 8,9). 
When the spores are ripe, the erect hyphe supporting both 
stellate threads and basidia, along with the latter, disappear, 
leaving the coloured star-shaped bodies mixed with spores, 
resting on the horizontal interwoven basal stratum of the plant. 
The object of this differentiation is not evident; but itis not the 
only instance where an apparently useless complex arrangement 
evolved in simple types, and afterwards suppressed, manifests 
itself again in more highly organized forms in connection with 
some important function, as illustrated in the structure of the 
Polypore: already alluded to. 
A similar differentiation is met with in Bovista, a genus belong- 
ing to the Gastromycetes, where a compact external layer forming 
the peridium is composed of colourless thin-walled septate hyphe, 
from one side of which spring numerous branches, some giving 
origin to basidia, others to variously branched, thick-walled, dark 
brown, aseptate hyphe, collectively constituting the capillitium, 
which, along with the spores, are eventually free, owing to deli- 
quescence of the supporting threads. The only morphological 
distinction of importance between Asterostroma and Bovista 
consists in the former having the basal stratum, from which 
basidia and coloured hyphz originate, effused and adnate to the 
substratum, with the upper free surface everywhere covered with 
the hymenium; whereas in Bovista the corresponding stratum 
forms a hollow sphere, the outside of which corresponds to that 
portion in Asterostroma attached to the substratum, while the 
inner surface, which corresponds to the upper surface in Astero- 
stroma, gives origin to the spore-producing structures and capil- 
litium, which are consequently concealed. From the above 
description it will be gathered that the conception of Bovista is 
nothing more than that of a closed-up Asterostroma, an idea 
