OF FILAMENTOUS, FRUTICULOSE, AND FOLIACEOUS LICHENS. 257 
warts, scattered on the thalline lacinia. The spermatia are rod-shaped, about 
gath long, and sath broad. The arthrosterigmata resemble those of Sticta or 
Collema—the cellules or articulations being short, broadish, and thick-walled. 
GENUS III. Coccocarpia, Pers., Nyl. 
_ The spermogones of this genus resemble those of Ricasolia somewhat, being 
largish superficial papillae or tubercles, having rod-shaped spermatia on arthro- 
_sterigmata. They are generally seated about the periphery of the thallus, out- 
side the region occupied by the apothecia. Sometimes they are arranged longi- 
tudinally, or in the line of radii passing from the centre to the circumference of 
_ the thallus; sometimes in arcs parallel to the zones which mark distinctly the 
development of the thallus. They are generally of the colour of the thallus, 
| the ostiole being usually brown or black. In C. molybdeea, they are pale yellow, 
| with a brown ostiole. They are frequently confluent, becoming then very irre- 
gular inform. The ostiole is seldom round, and this only in the young or mature 
state. Subsequently it becomes generally elongated or chink-like, and more or less 
irregular in outline. The body of the spermogone forms a dense, hard, whitish or 
| yellowish kernel, immersed in the medullary tissue of the thallus. The envelope 
/is generally of a pale-brown or brownish-yellow cellular tissue. The sterigmata 
are ramose, longish,—;th to ;th in length in C. plumbea,—with a breadth 
of a,th, composed of short roundish or cubical thick-walled cellules. In the old 
spermogones, the sterigmata frequently acquire a brown colour, especially below, 
‘and they sometimes become aggregated into a compact tissue, which fills the 
cavity of the spermogone. This tissue, in some cases in C. plumbea, may even 
‘become black. The diameter of the cavity of the spermogone in C. plumbea 
|is 4th to ath; the spermatia are rod-shaped, and about goth to zath long, with a 
| breadth of sooth to sooth. NyYLANDER’S distinction between Coccocarpia and 
: Pannaria seems to me a very insufficient and unsatisfactory one :—“ Nimis arcta 
est affinitas inter Coccocarpias et Panarias,” he himself admits. ‘In Coccocarpiis 
thallus ad formam radiato-sub-monophyllinam tendens (spe concentrice versus 
‘ambitum rugulosam) et apotheciis constanter biatorinis levem offert differentiam 
a Pannaris.”* 


Species 1. C. plumbea, Lightf., 
| Which occurs in North Africa, as well as in Europe; a familiar British species. 
'The spermogones are sometimes inconspicuous from being of the same colour 
| with the thallus; the ostiole, however, is generally of a deep brown, sometimes 
‘black, colour. They are large, flattened tubercles—frequently elongated in the 
‘direction of the radiations of the thallus—often confluent and very irregular in 
‘form. The cavity is simple. In old spermogones, the sterigmata frequently 
/assume a brown colour, and become agglutinated into a compact tissue. 
| * Enumération Générale des Lichens, p. 109. 1858. 
VOL. XXII. PART I. 3 U 
