British Gasfromycetes. 15 
hymenial elements. The threads forming the capillitium are 
modified branches originating from the thin-walled hyphae 
of the trama or the peridium, and are usually aseptate or 
with only an occasional septum. The statement made by 
De Bary that ‘ the threads in Bovista have no transverse 
walls 1 ,’ is only true of some few species, as in several South 
American plants belonging to this genus septa are constantly 
present. 
It is generally supposed that the capillitium exercises some 
function in connection with spore-dissemination ; but if so the 
exact way in which it acts is as yet unknown. The threads 
do not possess any marked hygroscopic property. The state- 
ment by De Bary, that thickened walls of the capillitium in 
L. bovista are furnished with pits 2 , I have not been able to 
verify. In Battarrea phalloides a few of the threads contain 
well-developed spiral or annular thickenings in their interior 
(Fig. 29, b). In Bovista and Lycoperdon the peridium consists 
eventually of two distinct layers. In the last-named genus 
the outer layer, consisting of large thin-walled cells, soon fails 
to keep pace with the growth of the inner layer, and is con- 
sequently broken up into mealy granules. In most species 
these granules continue to grow at the base, and owing to the 
expansion of the inner layer of the peridium become separated 
from each other, eventually assuming the form of pyramids or 
spines which are frequently curved, and often split in a fibrous 
manner at the base and become rigid owing to partial dis- 
integration of the walls. In many species the large spines are 
surrounded by a ring of small warts which persist after the 
former have fallen away (Fig. 32). In Bovista the outer layer 
of the peridium is continuous, but owing to early gelification 
of the walls, forms a friable crust, which breaks away in 
patches. In both genera the inner layer consists of inter- 
woven hyphae and is persistent until the spores are mature, 
when disintegration takes place at the apex, and an opening 
is formed for the escape of the spores. 
1 1 . c. p. 3T4. 
2 l. c. p. 314. 
