134 MISSOURI BOTANICAL GARDEN. 
Subclass: (a) Condition of the mycelium. (6) Distribution of 
the gonidia. 
Order: (a) Type of apothecia. 
Suborder: (a) General form of apothecia. (6) Development of 
spores. 
Group: (a) General form of the thallus. (b) Habit of growth— 
attachment. 
Family: (a) Form of thallus. (6) Structure of apothecia. (c) 
Type of gonidia. 
Tribe: (a) Type of cortical structure. (6) Type of medulla. 
Genus: (a) Structure of the thallus. (6b) Type of spore. (ce) 
Form of apothecial margin. 
Section: (a) Number. (b) Form. (c) Color of the spores. 
Series: (a) Peculiarities of thalline structure. 
Species: (a) Differentiation of the thallus or spores. 
Variety: (a) Constant morphological variation of the thallus 
or spores. 
Phase: (Without name) (a) Type of reproduction. (b) Color 
—dicroic. (c) Contingent conditions. 
The genera afte here constitute the Family Usneacex 
have been assem led under groups variously titled and of 
widely varying { eneric composition. First included (plus 
p.) in Linneus’ Filamentosi, they have appeared since 
under Ramalodei, Thamnoblastex, Parmeliacex, Radiatex, 
etc. The grouping of the present genera has caused, except 
in the case of Teloschistes, but slight taxonomic dislocation. 
The main question for argument seems to lie in whether the 
grouping of genera had best follow phylogenetic indications 
supplied by spore characters? or by thalline affinities. 
Teloschistes flavicans var. capensis (L. fil) Nyl. certainly 
argues a close thalline relation in this recently introduced 
genus, and it is interesting to note that Hoffmann called 
this a species under the name Usnea capensis. (See 
diagram. ) 
2See Hue, Bull. Soc. Bot. France 58 : 1911. 
