4 ICONES MUSCORUM. 



A very distinct species, in size and habit resembling large 

 forms of Sphagnum cymbifolium; agreeing also with that species 

 in the scabrous dorsal apex of the leaf, and in the presence of 

 spiral fibrillae in the cortical cells of the stem and branches, a 

 structure found in no other Sphagnum. 



The principal characters separating this species from 6'. cym- 

 bifolium are the attenuated base of the branches; the fringed 

 margin, suddenly contracted base, and different cross-section of 

 the leaf; the absence of pores in the cortical cells of the stem, 

 and their rare occurrence in those of the branches ; and, espe- 

 cially, the peculiar form of the latter cells, which are suddenly 

 bent or sagged in the middle, so that in cross-sections of the 

 branch they give the appearance of being disposed in two or 

 three layers, instead of one, as is really the case, as shown in 

 fig. 7, sections being made at the dotted lines ab, cd, and ef. 



A distinctive character is also seen in the large hyaline cells 

 near the base of the branch-leaf, which, within and along that 

 portion of their walls in contact with the small chlorophyllose 

 cells, are beset with papillae or short spines (figures 11 and 12). 



TAB. 2. — Sphagnum Portoricense. 



1. Planta naturali magnitudinc. 



2. Para caulis cum ramulorum fascicule 

 '■'•. Pars caulis transversim sectae. 



l. Folium caulinum. 

 5. Ramuli sectio transversal is. 



ti. Ramuli pars externa, cellularum corticalium formam lineis punctatis par- 

 tim adumbrans. 



7. Ejusdem sect, longitud. easdem cellulas in medio geniculatas monstrans. 



8. Folium e ramuli medio desumptum. 

 Ejusdem apex a latere visa. 



10. Ejusdem sectio transversalis. 



1 1. Particula ejusdem sectionis, cellulas hyalinas intus papillosas exhibens. 



12. Folii ramulini angulus basilaris, auriculas et cellulas hyalinas intus pa- 



pillosas monstrans. 



13. Cellulse e folii ramulini media parte. 

 1 I. Eaedem e parte superiore. * 



15. Folii particula emu cellulis partim dissolutis Bmbriam formantibus. 



