414 



ridia ovoid-oblong, continuous, subhyaline. The genus has the habit 

 of Phytlachora or Rhytisma. 



T. quercina, (Pr. & Rud.) (Plate 31) 



Rhytisma quercinum, Fr. & Rud. iu Iviun. Trans. 1830, p. 551, 

 Asieroma parmelioides, Dqsm. PI. Crypt. Ed. I, 1737. 

 Rhytisma riccioides, IvCteliier Champ. V, tab. 629, figf. 4. 

 Sphceropsis riccioides, I^ev. Ann. Sci. Nat. III. Ser. torn. p. 257. 

 Trabutia quercina, Sacc. & Roum. 1. c. 

 Bxsicc. Thum. M. U. 2271.— Ell. N. A, F. 1288. 



Perithecia hemispherical, subcarbouaceous, shining-black, with a 

 minute, round, perforated ostiolum, finally collapsing and umbilicate or 

 subplicate, but never opening as in Rhytisma. Asci cylindric-clavate, 

 100-110x18-21 fi, paraphj^sate, membrane entire at the apex, short- 

 .stipitate, soon disappearing. Sporidia biseriate, oblong-navicular, ends 

 subobtuse, 28-30 x 8-10 jx. 



On leaves of Quercus laurifolia and Q. virens, Florida and 

 Mississippi. 



T. tosta, (B. & C.) 



Rhytisma tostutii, u. & C. Grev. IV, p. 9. 

 Trabutia tosta, Cke. Syn. 1372. 



" Seated on yellow spots, thin, gyrosc, only hero and there pro- 

 duciiig fruit-bearing perithecia which soon shell off. Undoubtedly 

 distinct, but the specimens are imperfect." 



On leaves of Quercus laurifolia, Alabama. 



T. erythrospora, (B. & C.) 



Rhytisma erythrosporunl, B. & C. Proc. Am. Acad. IV, p. 128. and Grev. IV, p. 9. 

 Trabutia erythrospora, Cke. Syn. 1371. 



" Minute, opening with two or three laciniae. Asci swollen. Spo- 

 ridia subfusiform, salmon-colored, apiculate at each end, .33 ji long. 

 On leaves of Quercus virens, Califoi'nia. 

 The manner of dehiscence indicates Rhytisma. 



THYRIDIUM, Sacc. 



Mich. I, p. 50. 



Perithecia scattered or gregarious, immersed in the more or less 

 altered substance of the wood or bark, and covered above by a prom- 

 inent, black, stromatic shield. Ostiola papilliform. Sporidia subellip- 

 tical, brown or hyaline, muriform. 



Th. lividum, (Pers.) 



Spheeria livida, Pers. Syn . p. So. 

 Teichospora livida, Karst. Myc. Fenu, II, p. 68. 

 (Fenestella) f livida, Winter Die Pilze No. 4251. 

 Thyridium lividum, Sacc. Syll. 3991, Cke. Syn. 3981. 



