LECIDEACEAE


Thallus crustose, without plectenchymatous cortex (Fig. 2, a), varying
from granulose and often evanescent to conspicuous, areolate, or even
subsquamulose conditions, attached to the substratum by hyphal rhizoids
(Fig. 2, d), and in a few instances extending up as a veil and
surrounding the apothecia laterally, the hyphae densely interwoven
toward the upper surface, but more loosely disposed below (Fig. 2, a and
b); apothecia usually minute or small, commonly rounded, the exciple
weak and obscure (Fig. 10, d), or more strongly developed when
conspicuous and much darker in color (Fig. 11, b); hypothecium varying
from hyaline to dark brown (Fig. 10, b and Fig. 11, c); hymenium almost
always lighter and commonly hyaline (Figs. 10 and 11, a); paraphyses
usually simple, but branched forms to be found frequently (Figs. 1 and
12), pale throughout or darkened toward the sometimes enlarged apex,
commonly more or less coherent and indistinct at maturity; spores simple
and hyaline to muriform and brown (Figs. 2, 3, 4, 5, 6, 7, 8, 9, and
13).


KEY TO THE GENERA

Spores minute, numerous in each ascus _Biatorella_, p.
Spores larger, usually 8 in each ascus,
Spores hyaline.
Spores one-celled (simple) _Lecidea_, p.
Spores more than one-celled (compound).
Spores 2-celled _Biatorina_, p.
Spores 4- to several-celled.