22S GYROSTOMUM. 



Wright The lichen is very near to T. compunctum (Sm.) 



Nyl. (Wright Lich. Cub. n. 152 ; Lindig Herb. N. Gran. n. 2855), 

 but differs in the ultimate development of its fruit, and dis- 

 tinctly smaller spores. The white exciple which is so conspic- 

 uous in the dilated condition of the apothecium is clearly iden- 

 tical, as respects at least its interior portion, with the interior 

 exciple which makes the only visible envelope in T. com- 

 punctum, however undistinguishable finally from the thallus. 

 I see no reason to question this view (Genera Lichenum, p. 136) 

 which applies to not a few other species in which the interior 

 exciple has been wrongly taken for the proper exciple. 



12. T. Wightii (Tayl.) Nyl. ; thallus coriaceous-cartilagin- 

 eous, smooth but minutely rugulose ; greenish-glaucescent and 

 cinerascent ; shewing, in section, scarlet particles here and 

 there within ; apothecia very minute, included in the thallus ; 

 and offering only a pore-like aperture bordered by the entire, 

 pale interior exciple which is concrete with the thallus. Spores 

 rounded and ellipsoid j dark-brown ; the transverse series of 

 spore-cells about four, soon irregularly disposed ; ^ mic. 

 Endocarpon, Tayl. in Hook. Journ. Sot. 1847, p. 155. Thelo- 

 trema, Nyl. N. Gran. p. 50, & in Herb. Lindig n. 2662. T. Eav- 

 enelii, Tuckerm. Suppl. 1, I. c.p. 426. 



Trunks, low country of South Carolina to Texas (Ravenel), 

 Tuckerman I. c. 1858. Louisiana, Hale. 



I2(b). T. Eavenelii (Tuckerm.) Nyl. ; thallus thinner for the 

 most part, and without the scarlet particles of the preceding ; 

 apothecia perhaps a little larger and more open; and the excip- 

 ular margin blackening. Spores pale-brown j oblong-ellipsoid ; 

 narrower j the transverse series of spore-cells commonly six to 



eight j ^^ mic. Nyl. N. Gran. p. 50, note. Tuckerm. Gen. 



p. 139. 



Trunks, South Carolina (Bavenel), Nylander I. c. 1864. 

 Alabama, Beaumont. Close enough to T. Wightii, but offer- 

 ing the differences noted. 



XXXVIII. GYROSTOMUM, Fr. 



Apothecia from urceolate becoming explanate; either 

 orbicular or oblong ; consisting of a black proper exciple 

 with entire margin, clothed more or less with a finally dis- 



