Species of Xerula from sub-Saharan Africa

Fungal Diversity
Figs 27-29. Xerula mammicystis (from holotype). 27. Basidia and basidiospores. 28. Cheilocystidia. 29. Caulocystidia.
Left, from stipe apex; right, from stipe midsection. Bars = 20 µm.
(Fig. 28) welldeveloped, of two types: 1) 39-68
× 17-23 µm, pedicellate, broadly clavate,
thinwalled, clamped; contents homogeneous,
hyaline in small individuals, distinctly pigmented
olive-brown in largest; and 2) 122-136 ×
38-40 µm, long-pedicellate, clamped, fusiform
to broadly fusiform, usually mammilate, thickwalled
(wall up to 3 µm thick over bulb);
contents homogeneous, hyaline. Caulocystidia
from stipe apex (Fig. 29) 52-125 × 20-36 µm,
not pedicellate, broad at base (5-7.5 µm broad),
obscurely clamped, thin-walled but with
coagulated protoplasm appearing irregularly
thickwalled, hyaline, in discrete sori. Caulocystidia
from stipe midsection (Fig. 29) arising
from heavily pigmented outer stipe surface
layer, in indiscrete sori, 85-178 × 15-19 µm,
slender proximally, cylindrical to rarely
clavate, thick-walled (wall 1-2 µm thick),
obscurely clamped; contents homogeneous,
distinctly olive-brown.
Commentary: With only two basidiomata
of the type specimen to represent the species,
little can be reported about infraspecific
137