A Bee-hive Fungus, Pericystis alvei, Gen. et Sp. Nov. 
BY 
ANNIE D. BETTS, B.Sc. 
With Plates LXXV and LXXVI. 
HE bee-hive Fungi, as a class, have been studied but little, though 
X bee-keepers have long been aware of the occurrence of ‘ mould ’ in their 
hives, and some of the diseases to which the honey bee is liable are known 
to be of a fungous nature. An investigation was begun with the object of 
filling this gap in our knowledge of the economy of the hive ; in the course 
of it, the species which is the subject of the present paper was met with. 
Pericystis alvei is a common fungus, being in fact the principal consti- 
tuent of the ‘pollen-mould’ prevalent in hives during the winter and early 
spring. It grows, as this name indicates, on the pollen stored in the combs 
(PI. LXXVI, Fig. 1 1), and is not found, so far as is known, on any other sub- 
stratum. The contents of cells attacked by the fungus tend to dry up 
ultimately into hard plugs, which often split into layers (see PI. LXXVI, 
Fig. 12) ; they are permeated by mycelium, which is, however, most plentiful 
on the surfaces and especially on the top (that is, the surface exposed when 
the plug is in the cell). 
This species may be readily distinguished from all others found in the 
hive by the character of its mycelium. Many of the hyphae have a large 
proportion of their cells converted into chlamydospores ; this is sometimes 
carried so far as to give the appearance of an oidium-hypha (PI. LXXV, 
Fig. 2, b). The remaining cells tend to lose their protoplasmic contents, 
so that the hyphae when mature break up readily (Fig. 2, a). Other 
hyphae are more or less devoid of spores, or only bear occasional lateral 
or intercalary ones (PL LXXV, Fig. i,a). 
The hyphae are 2-6 \x in diameter. As a rule, they assume their 
characteristic appearance when quite young (PI. LXXV, P'ig. 3, a } where 
chlamydospore is shown in course of formation on a young hypha). 
The chlamydospores are of various forms (Fig. 3). In position they are 
terminal, lateral, or intercalary, or are borne on short lateral processes 
(PL LXXV, Figs. 1,2). Their dimensions vary from 4-5 \x to 9-5 x 7 jotor even 
Annals of Botany, Vol. XXVI. No. CIII, July, 1912.3 
