On the Marine Algæ from North-East Greenland. 



101 



Lithophijllum lœve Strömfeit (1886) p. 21 pi. I fig. 11-12. 

 Lithothamnion tenue K. Rosenvinge (1893) p. 778 ex parte. 



This species has been collected in considerable quantities in 

 various localities; it is the species of Lithothamnion most represented 

 in the collection. It forms extended thin crusts over stones, and 

 further over shells of bivalves and of barnacles. Usually it has 

 conceptacles of sporangia the diameter of which most frequently 

 attains or even exceeds 1 mm. The sporangia contained in all 

 examined cases two spores only; they were 240—360/^ long, 93— 

 167// broad. According to Foslie, (1905), p. 18 and 53, the sporangia 

 are four-parted ; he says how^ever that he has "often seen two-parted 

 ones, sometimes even only two-parted ones, particularly in the nor- 

 thern part of the arctic zone. But having found in other specimens, 

 partly from the same places, both two-parted and four-parted ones, 



Fig. 1. Lithothamnion lœve, sporangia. A — C from the same 

 conceptacle, D — F from another conceptacle. 95 : 1. 



sometimes even in one and the same conceptacle, I think it fair to 

 presume that the two-parted ones have not been fully, or normally 

 developed". The fact that I have found only two-parted sporangia 

 in all, not few, examined cases, seems however to favour the belief 

 that this species has only two-parted sporangia in this arctic region. 

 The only argument which could be alleged against this is, that all 

 the specimens in question are collected in August and September 

 and that the sporangia possibly at a later period might be four- 

 parted. After what is known about the fructification of these Algæ, 

 that supposition is however little probable. As shown in fig. 1, the 

 breadth of the sporangia is rather variable, partly according to their 

 place in the conceptacle. 



Specimens with sexual conceptacles were also found, though in 

 lesser quantity. These conceptacles are easily recognizable from 

 their conical form and smaller diameter; the conceptacles of cysto- 

 carps were 500—800// broad, those of antheridia 500 — 600//. 



Loc. Along Cape lîisniarck Peninsula; in and off tlie entrance to tlie 

 harbour; at Vestre Mavnenæs, 28 meters; off liaadskæret, 19—47 meters. 



