69 



main-axis, from which the more or less spreading and sparsely 

 divided branches frequently issue in all directions. The branches 

 never are straight, but more or less curved, or angularly bent, 

 terete, either nearly equal in thickness, generally 1.8—2.2 mm., or 

 often rather attenuating towards the tip, with rounded ends, or 

 now and then somewhat rounded-thickened ends. They partly 

 are free everywhere partly in more densely branched specimens 

 more or less anastomosing below, but upwards always spreading. 

 PI. 16, fig. 43 — 50. The surface of the frond sometimes is smooth 

 sometimes and more frequently finely rugged and squamellate. 



With regard to the structure this plant is in general coarser 

 than the preceding species and most nearly agreeing with that of 

 L. fruticulosum. In a longitudinal section of a branch the inner 

 cells of the cup-shaped layers of tissue are 8 — -12 <i long, fre- 

 quently about 8—10 p, and 6 — 7 fi thick. 



The conceptacles of sporangia are crowded in the upper part 

 of the branches without any order, convex, but little prominent, 

 rather reminding one of those in certain forms of L. fruticulosum, 

 but frequently larger, seen from the surface 300 — 350 or occasio- 

 nally up to 400 p. in diameter and often not distinctly marked. 

 The roof is rather thick and intersected with about 30 muciferous 

 canals. The sporangia most probably are tetrasporic, but I have 

 not seen any with distinct partition, about 120 p. long and 40 p 

 broad. However, I have seen but a very few. The conceptacles 

 finally grow down into the frond. Overgrown ones sometimes are 

 scarce sometimes rather numerous, chiefly in the peripherical por- 

 tion of a branch, but they are on the other hand often apparently 

 wanting. I have not seen conceptacles of cystocarps. 



Remark on the synonomy. Most of the specimens recorded 

 1. c. under the name of L. norvegicum f. distcms belong to the 

 present species. I then had not the advantage of examining more 

 thouroughly a greater number of specimens of the different forms. 

 L. norvegicum was a little known plant, of which only sterile 

 specimens were known, and as this together with the forms now 

 separated often closely approach each other in habit, I considered 

 them to belong to one and the same species. 



