66 



attached to the top of a papilla, while the adjacent carpogoniiim has divided by a 

 transverse wall after fecundation; the fertilization-canal of this carpogoninm is yet 

 to be seen below. The carpogonia produce 4 or 8 spores in Iwo layers. 



This species seems to disappear during the summer. On July 2"'' 1905 on 

 the moles of Ihe harbour of Skagen I only found some very small specimens 1 — 

 1,5 cm. high, being evidently the under part of specimens which had exhausted 

 their spermatia and carpospores; there were namely still to be seen remnants of 

 emptied antheridial sori and some few cyslocarps containing 8 spores, while the 

 upper border of the frond consisted of emptied cell-walls (Plate II fig. 9 — 13). In 1907 

 the species remained longer, perhaps in connection with the fact, that the summer 

 was unusually cold with predominant westerly winds. On July 11"' 1907 I found 

 in the same locality rather large specimens, some of which showed antheridia, 

 in part not emptied, and cyslocarps. Other specimens did not show these organs 

 and did not seem to have produced them earlier. In such a specimen the cells in 

 the upper part of the frond had more granular contents than the vegetative cells, 

 for which reason I am inclined to believe, that they were producing gonidia (Plate II 

 fig. 8). These cells had a sharply limited lateral vacuole; thej' were not divided by 

 walls parallel to the frond. 



Kylin (1907 p. 110 Taf. 3 Fig. 1) has established a species nearly related to 

 P. leucosticta under the name P. elonyata (Aresch.) Kylin iP. laciniata var. Areschoug 

 Alg. Scand. exsicc. No. 117), which is distinguished by its elongated form of frond 

 with uniform breadth, its thinner frond (25 — 33 ^ while it is said to be 33 — 40 n 

 in P. leucosticta), and the smaller antheridial sori; it may he added that the 

 author found it epiphytic and fructiferous in August. It appears to me, however, 

 to be rather doubtful if it can really be regarded as a species distinct from P. leu- 

 costicta; at all events, the alleged characters are hardly conclusive. As said above 

 leucosticta has often a lingulate form (comp. PI. II fig. 4 — 8), and that is so also 

 in specimens from the coasts of France. The thickness of the frond was found, in 

 the Danish specimens of this species, to vary on both sides of the limit given by 

 Kylin (se above). That the sori of antheridia in the specimens of Kylin reached 

 only a size of 2 mm., while they attained a length of 10 mm. in the Danish spe- 

 cimens, is scarcely sufficient for specific distinction. I have found no specimen on 

 the Danish coasts fully agreeing with P. elongata Kylin, the specimen most similar 

 to it was 16 cm. long, 2 cm. broad, on the one side with a small lobe; it had a 

 thickness of 28 u, but the antheridial sori were long. 



The plant grows on stones at the mean level of the sea. 



Localities. Sli: Hirsiials, on tlie mole and on a large boulder on the shore, April 1906. 

 Kli : Harbour of Skagen; it appeared contemporaneously with the construction of the harbour; it was 

 detected by Mag. M. L. MoiiTKNsiiN, "I4 1905, on the moles commenced the preceding year and constructed, 

 as far as known, e.xclusively of stones taken on land. Later, 1 have found it, on several visits in April 

 and .luh', on the outer and inner sides of the moles, but only or principally near land. 



