104 



Addition to the description of the species. Most of the spe- 

 cimens of this species that I have seen are thinner and younger 

 than those mentioned by Kjellman 1. c, the crust only 1 — 2 

 mm. in thickness, but bearing conceptacles of sporangia, a couple, 

 however, even up to 2.5 cm. thick, with numerous new crusts 

 formed upon the primary. The surface of younger individuals is 

 even and smooth, in older it often becomes somewhat uneven, and 

 once I even found a couple of very small excrescences. It partly 

 is feebly shining partly not, and especially old individuals appear 

 frequently to be dull or nearly dull. PL 19, fig. 1 — 4. 



The conceptacles of sporangia are rather densely crowded 

 over the whole frond without any order, occasionally so densely 

 that they become angular, and even close to- the margin of the 

 crust. They appear from the surface at first as small and lighter 

 points, which soon become a little larger and by and by depressed, 

 towards maturity forming nearly cup-shaped but shallow deepenings 

 about 150 — 200 /j. in diameter, a smaller central portion frequentty 

 gets more depressed, about 100 fi in diameter, and this portion is 

 intersected with 10 — 20 rather coarse muciferous canals. Occa- 

 sionally they somewhat approach those of L. incrustans in appea- 

 rance. At maturity the named central portion of the roof falls 

 away, and the surrounding parts, sometimes become lighter and 

 easily dissolvable sometimes not, the peripherical portion or thicke- 

 ning layer of the frond continues its growth and the conceptacles 

 become overgrown. Now and then the whole roof falls away, 

 probably on account of external causes, or if the conceptacles are 

 very densely crowded, and then the emptied conceptacles form 

 distinct and rather deep holes about 200 — 250 p- in diameter. These 

 holes often get effaced by new local formations of tissue, and such 

 filled conceptacles are to be seen on a section. Overgrown con- 

 ceptacles partly are numerous partly very few, on a radial section 

 forming more or less regular rows parallel to the surface of the 

 frond. I have seen but some few sporangia, which were bisporic, 

 but I do not know whether they were quite mature, 120 — 160 />- 

 long and 50 — 80 ;i broad. Cp. Rosen v. 1. c. The cell-rows of 



