INTRODUCTION TO BOTANY. 
223 
Lichens. 
Frond, From , Thallus , Receptaculum universale . The 
frond or cormus of a lichen, containing sporee or gongyli 
dispersed through its substance. 
Fibrils, Fibrillce. The rootlike holdfasts. 
Cortical substance, Substantia corticalis . The external 
substance of the frond. 
Medullary substance, Substantia medullaris. The internal 
substance of the frond, when it can be distinguished. 
Podetium. An elevation of the thallus raising up the 
apothecia. 
Podicellum. A very small, short podetium. 
A pothecium ^Thalamus , Receptaculum par tiale. The par- 
tial receptacle of the gongyles either sessile or raised upon 
a podetium, that are placed on the frond. 
Apothecia vera , Organa foe mina. The apothecia that are 
more constant in their appearance, and of which only one 
kind are found in the same individual. 
Apothecia spuria , Apothecia accessorial Organa mascula . 
The apothecia less constant, and of which several kinds are 
sometimes found on the same plant, including cephalodia, 
cyphellse, pulvinuli, and perhaps soredia. 
Scutellce . Orbicular sessiie apothecia surrounded by an 
edge similar to the thallus. Parmelia. 
Patellulce. Orbicular sessile apothecia, with a border 
not similar to the thallus. Lecidea. 
Lirellce. Sessile, linear, winding apothecia, opening by 
a longitudinal slit. Opegrapha. 
Pilidia. Orbicular, hemispherical apothecia, whose sur- 
face resolves into a powder. Calycium. 
Orbillce. Apothecia placed on podetia, enlarged into a 
disk, fringed or radiated on the edge. Usnea. 
Peltce. Rather leatherlike apothecia, on the edge of the 
thallus, without any edge, or a very narrow one, and co- 
vered at first with a thin, gelatinous membrane. Physcia. 
Tricee , Gyromata . Orbicular, sessile apothecia, with 
rising folds in a spiral form, opening longitudinally, and 
emitting capsules, or elytrae, containing eight spores each. 
Mammula. Apothecia which are sessile, but are more 
convex than the scutellae or patellulae, and have neither 
edge or border. Coniocarpon. 
Tuberculee. Spherical apothecia, which ' contain within 
them agglomerated globular spores. Verrucaria. 
