126 LICHENACEL. [cLADONIA. 
32. CLADONIA Hill. 
Hist. Pl. (1751) p. 91 W) 
pro parte; Hoffm. D. Fl. 7 => 
ii. (1795) p. 114; Nyl. o\ ’ 
Not. Sallsk. pro F. et Fl. 
Fenn. Forh. n.s. v.(1866) Co 
p. 110.—Thallus laci- b , 
niato-foliaceous or squa- 
moso-foliolose at the base ; @ EX 
podetia branched or scy- d . ¢ 
phiferous, more or less 
pulveraceous or squa- 
mose, entire or with the Fig. 35. 
axils and seyphi perfo- Cyagonia pyxidata Fr.—a, Vertical section of 
rate. Apothecia termi- an apothecium, x30. J. Theca and para- 
nal, at first somewhat  physis, x350. ¢. Spores, x500. d. Vertical 
plane and margined but section of a spermogonium, x30. e. Sterig- 
immediately be ee e mata, and f, spermatia, x 500. 
convex and immarginate ; 
spores 8nx, oblong, simple, colourless. Spermogones usually situated 
on the ae of a ee conical ; spermatia equally cylindrical, 
somewhat curved or straight. 
The species of this genus are for the most part very variable. They 
are consequently so connected by intermediate states and forms (the 
result to a certain extent, perhaps, of hybridism) that it is sometimes 
difficult to separate them. Unfortunately, also, the chemical thalline 
reactions, apart from the characters of the basal thallus and the podetia, 
are not of decided value here *. 
Sometimes there is seen a thin extended hypothalline-filamentose 
patch, in which originate the basal squamules. 7 Phe thallus is loosely 
affixed by these filaments to the substratum, and in some instances, where 
they decay, it becomes free. The spores and the spermatia of the dift 
ferent species do not vary much in size, the former being 0,008-0,015 mm. 
long, 0,003-0,004 mm. thick, and the latter 0,008-0,012 mm. long, scarcely 
0,001 mm. thick. The genus may, for convenience, be divided into the 
following sections from the colour of the apothecia. Some plants of this 
and the following genus, when growing in dry exposed places, become 
more or less cervine or brownish, whence vars. spadicea, fuscescens, &c., 
of authors. 
Our islands are peculiarly rich in Cladonias; further research will no 
doubt bring additions to light, as well as extend the distribution of some 
already detected. 
* Nylander says :—‘ The genus Cladonia is not well adapted to show the 
excellence of reactions, on account of the tinctorial particles being ften but 
sparingly present, by reason of the tenuity commonly of the cortex.”—‘ Flora,’ 
1886, p. 101. 
