308 PALMELLEiE. 



1. Palmella ceuenta Ag. 

 Plate LXXX. Fig. 5. 



Char. Frond indefinite, crustaceous, expanded, blood-red, 

 tuberculate, filled loith subangular hyaline globules, and 

 '' very minute punctiform scattered granules.^'' 

 Tremella omenta, E. Bot. t. 1800.; Grev. Crypt. Flor. 

 p. 205. ; Hook. Brit. Flor. vol. ii. p. 396. ; Harv. in 

 Manual, p. 179. 

 Hab. On clamp walls, chiefly such as are whitewashed ; 

 often in cellars. Glasgow : Sir W. J. Hooker. On 

 damp walls near the ground at Mayfield and elsewhere, 

 frequent : Mr. Jenner. 

 " The red spots in the beginning irregularly orbicular, 

 quickly becoming confluent, attached to earthy particles, to 

 stones, and other extraneous substances, form a Avidely ex- 

 panded crust, which, on the application of moisture, swells 

 up, and then especially resembles coagulated blood. By 

 drought their young frond grows dusky and disappears ; but 

 more evolved, it dries up, and is more intensely coloured ; it 

 cracks, curls up, and falls in pieces. Rainy weather con- 

 tinuing, and other Algoz being evolved amongst it, especially 

 Oscillatoria autumnalis and Microcystis atrovircns, it be- 

 comes green, and at length black. If the crust be kept 

 immersed some hours in Avater, it swims on the surface 

 like a thin pellicle. A morsel of this subjected to the 

 microscope presents hyaline globules, subangular, and adorned 

 with a faint carneous tint, which are so closely heaped toge- 

 ther, that at first sight they appear to form a cellular mem- 

 brane. Nevertheless they are not joined by any adherence, 

 as is evident from the fact that they recede from each other 

 under the object glass itself with the slightest pressure. The 

 mucous, colourless substratum and punctiform granula or 

 lesser globules, more intensely coloured, then come into sight. 

 Moreover, a fragment of the frond itself, first submerged in 

 water, submitted to microscopic examination, manifests the 

 same organs, though less appressed, and the mucous sub- 

 stratum, endowed with more consistence, is detected." 



