94 



fj. long and 4 — 6 /j. thick, and often slightly smaller in f. norvegica 

 than in the other forms. 



I have examined hundreds of specimens from different tracts 

 and seasons, collected in May to October and in January and 

 March, but nearly all of them have been sterile, only a very few 

 ones of f. norvegica and f. saxatilis bearing organs of propagation. 

 I am, therefore, inclined to suppose, that the plant in all rather 

 seldom develops these organs. The conceptacles of sporangia 

 partly are scattered partly crowded in the upper part of the bran- 

 ches. They are slightly convex and very little prominent, the roof 

 frequently somewhat flattened in the central portion, 300 — 350 ^ 

 in diameter, most commonly about 300 p-, and in general a little 

 larger in f. saxatilis than in f. norvegica, intersected with rather 

 numerous muciferous canals, of which I have numbered about 50. 

 The sporangia are four-parted, in f. norvegica 100 — 130 /j. long 

 and 35—45 f* broad, in f. saxatilis frequently a little larger, or 

 110 — 140 /j. long and 40 — 55 broad. I, however, have seen but 

 few, especially in f. norvegica. Most of the sporangia in f. saxa- 

 tilis were only two-parted, but probably not fully developed, and 

 here I also found bisporic together with tetrasporic overgrown ones. 



The conceptacles of sporangia grow down into the frond, but 

 in f. norvegica they are extremely scarce. I have examined nume- 

 rous specimens without tinding any trace of overgrown organs of 

 that kind, but in others I found some few ones especially in the 

 peripherical portion of a branch, never in any great number, and 

 I occasionally met with overgrown conceptacles that had been filled 

 with local formations of tissue, as in other species before mentioned. 

 Once I even found a solitary sporangium in such a filled and 

 overgrown conceptacle. In f. saxatilis overgrown conceptacles 

 sometimes are not uncommon, sometimes apparently wanting, and 

 nearly always containing not escaped sporangia or such as have 

 not been mature before they as well as the conceptacles grew down 

 into the frond. On the other hand the whole roof appears now 

 and then to fall away, and in such cases the conceptacles appa- 

 rently not become overgrown, or the scars filled with local for- 

 mations. In the other forms they have not been found. 



