No. 3] REMARKS ON NORTHERN LITHOTHAMNIA. 55 



soriferum originally stated, the specimens from Honningsvaag 

 mentioned by Prof. Kj ell man 1. c. only bearing sporangia two- 

 parted. 1 ) 



The conceptacles of sporangia in L. topJiiforme, as observed, 

 are like those of L. soriferum. They are partly scattered, partly 

 densely crowded in the upper part of the branches, convex, but 

 little prominent, or subprominent, finally almost superficial, 300 — 

 500 \x in diameter. The roof is intersected with 50—80 muciferous 

 canals. The bisporic sporangia are 90 — 160 /v- long and 40—80/;- 

 broad. The conceptacles of cystocarps and antheridia are conical, 

 the former 400 — 600 f* in diameter, and the latter of about half 

 the size. In certain specimens of this species, the conceptacles of 

 sporangia are less prominent than usual, and are gradually over- 

 grown. Particularly in specimens from Greenland, I have some- 

 times seen rather numerous grown-in organs of that kind in the 

 peripheric portions of a branch, though more frequently the scars 

 from conceptacles emptied are effaced by local formations of tissue 

 and visible in a section. In most cases, however, the conceptacles, 

 when emptied, fall utterly to decay, and the said formations are 

 not to be seen in a section. 



I take each of the forms admitted above in a rather wide 

 sense, in the main corresponding to the forms of L. soriferum, 

 though more varying. Thus f. splicerica is in part quite like f. 

 globosa of L. soriferum. It is partly coarse, partly rather delicate 

 and more densely branching than usual, in the latter case greatly 

 approaching L. fomicatum or a coarse L. vardoense. Sometimes 

 the form also approaches L. Ungeri in habit. On the other hand, 

 this form even approaches -L. glaciale. This is the case particularly 



v ) I have not earlier had the opportunity of undertaking the extremely time- 

 wasting labour of going over each specimen, particularly of branching 

 Lithothamnia collected, for the purpose of searching for conceptacles and 

 sporangia, the less so because peculiarly older specimens are often sterile, 

 or fructiferous ones are only sporadically occurring, even among a largrf 

 number of collected specimens. In part I have also thought it uncalled for, 

 when the specimens in habit were quite like a species definite and appa- 

 rently well-known. It has, however, turned out that some of these speci- 

 mens bear sporangia two-parted, others four-parted ones. 



