196 PROCEEDINGS OF THE AMERICAN ACADEMY 



expansions, or external to the original thallus, forming new individ- 

 uals of the parent thallus ; and 2. by sporidia, consisting of sub- 

 globose or elliptical cells, which are either naked or contained in 

 other elongated more or less vertical cells {asci), and immersed in 

 the thalamium (or fructification proper), and propagate new individ- 

 uals of the species. The thalamium is either rounded, gelatinous- 

 waxy, and the asci converging {iiucleiform) ; or flattened at length into 

 a rigid, persistent, or afterwards collapsing lamina {subdisciform) ; 

 or originally disciform {open); and is itself contained in a receptacle 

 (exciple), either of the same color with and like the thallus {thaUine 

 exciple), or of different color and nature {proper exciple). The whole 

 fructification constitutes the apothecium, which is typically round, though 

 also occurring normally oblong and linear {lirellmform) , and is either 

 excavated with a contracted margin {urceolate) ; or slightly concave 

 with an elevated margin {scutelliform) ; or very concave-scutelliform 

 {cyathiform) ; or very concave-scutelliform and pervious {infundibuli- 

 form, a term applied also to the pervious cup-bearing podetia of Cla- 

 donise) ; or goblet-shaped and stipitate {craleriform) ; or dilated, flat, 

 and without prominent margin {peltc^form, of which the reniform is 

 a variation) ; or convex with repressed margin (cephaloid) ; or be- 

 tween scutelliform and peltseform (disciform) ; or between scutelli- 

 form and cephaloid {tuherculate). When the thalline exciple is pro- 

 longed below into a footstalk, it is said to be pedicellate; a proper 

 exciple in like manner prolonged is said to be stipitate. When the 

 proper exciple is originally and typically closed, the apothecium re- 

 ceives the name of periihecium. In the Angiocarpi several thalamia 

 are sometimes contained in the same exciple [composite apothecia) ; 

 and in the Gymnocarpi, in like manner, several disks are sometimes 

 confluent {symphycarpeous apothecia). The colors of the thallus in 

 Lichenes are disposed by Fries in four series : — 1. from pale green 

 becoming glaucous ; 2. from yellowish green becoming ochroleucous ; 

 3. from dark green becoming fuscous or olivaceous ; 4. from pale 

 yellow-green becoming lemon-colored. Each series has its peculiar 

 variations. The glaucous runs into pale green, cerulescent, and 

 white ; the fuscous into dark green, olivaceous, cinereous, grayish- 

 fuscous, and dark chestnut ; the ochroleucous into yellowish green 

 and albescent ; the lemon-colored into pale yellow, orange-red, and 

 vermilion-red. 



