Protonema.] ALG^E CHLOROSPERME^. 247 



soft cushion-like tufts, flexuose, irregularly branched, yellow- 

 green or orange ; articulations twice as long as broad. Harv. 

 in Hook. Br. Fl. v. ii. p. 380. Trentepohlia aurea, Ag. Syst. 

 p. 36. Conf. aurea, Dillw. t. 35. Byssus aurea, E. Bot. 

 t. 212. 



On rocks and old trees, common. 



2. C. Jolithus, Ag. Orange-red Croolepus. Filaments 

 tufted, erect, very short, orange-red, dichotomous ; articulations 

 once and half as long as broad. Ag. Syst. p. 34. Harv. in 

 Hook. Br. Fl. v. ii. p. 380. 



On rocks, in woods, &c. 



3. C. lichenicolus, Ag. Parasitical Croolepus. Tufts red- 

 orange ; filaments erect, fasciculated, alternately branched, 

 rigid ; articulations slightly tumid, as long as broad. Harv. in 

 Hook. Br. FL v. ii. p. 381. Conf. lichenicola, E. Bot. t. 1609. 



On Lichens and old trees. To me the three species of this section 

 appear to be merely varieties of one species. 



2. Black, torulose ; bearing clavate bodies resembling sporidia. 

 (Helmisporium ?) 



4. C. ebenea, Ag. Slack Croolepus. Filaments branched, 

 erect, tufted, rigid, sub-cartilaginous, black, obtuse; articula- 

 tions as long as broad. Ag. Syst. p. 36. Harv. in Hook. Br. 

 v. ii. p. 381. Conf. ebenea, Dillw. t. 101. Byssus nigra, E. 

 Bot. t. 702. 



On rocks and trees, in alpine districts. 



86. PROTONEMA. Ag. Protonema. 



Filaments sub-articulated, branched, rooting, mostly green. 

 Name ; irporos, first or primary, and vy/ma, a thread. These 

 obscure plants are probably rudimentary mosses. 



1. P. umbrosum, Ag. Shaded Protonema. Stratum vel- 

 vetty-green ; filaments erect, obtuse, fastigiate, fragile ; articu- 

 lations gibbous. Ag. Syst. p. 43. Harv. in Hook. Br. Fl. v. ii. 

 p. 383. Conf. umbrosa, Dillw. t. 61. 



On moist ground. 



2. P. cryptarum, Ag. Cave Protonema. Filaments dicho- 

 tomous, green ; branches divaricating, acuminated ; articula- 

 tions thrice as long as broad. Harv. in Hook. Br. Fl. v. ii. 

 p. 393 Conf. cryptarum, Dillw. Syn. t. D. E. Bot. t. 2588. 



In caves in the North of Ireland ; R. Brown, Esq. and Mr. Tern' 

 pleton. 



3. P. Orthotrichi, Ag. Parasitical Protonema. Filaments 

 olivaceous, minute, branched, obtuse, erect ; articulations about 



