73 



municated to me by Mr. Kolderup Rosenvinge nearly accords 

 with fig. 1 on pi. 17, but smaller, and two others and younger 

 also are so nearly agreeing with f. Oranii, that they in my opi- 

 nion must be referred to this form, with not or very slightly com- 

 pressed knobs or branches. The crust is in the specimens that I 

 have seen as thick or slightly thicker than in f. Granii, but Ro- 

 senvinge mentions thicker crusts, however, not being sure whether 

 they belong to the same form. Judging from these younger spe- 

 cimens the present form apparently also loosens itself from the 

 substratum, as they, being removed from the substratum, appear 

 to have been but loosely attached. Typical specimens of this form 

 have not been found with us, but only transitions to it. 



With reference to the structure both the forms accord with 

 one another. The branches show in a longitudinal section pretty 

 regular cup-shaped layers of tissue, with the inner cells about 

 10—12 [*■ long and 5 — 8 //- thick. 



The form Oranii develops sporangia at a rather young stage, 

 even before the branches are particularly developed. The concep- 

 tacles only occur in the upper part of the knobs or branches and 

 especially just below the apices, never in the crust. They are 

 partly somewhat scattered partly and more frequently densely 

 crowded, often so densely that the roofs become angular, or more 

 or less confluent, in this respect rather accordidg with those of 

 L. tojphiforme, seen from the surface about 350 (i in diameter, 

 sometimes less sometimes a little more, convex but little prominent, 

 and now and then somewhat flattened especially in a younger state. 

 The roof is traversed by about 30 muciferous canals. I have exa- 

 mined several sporangia, all of which were bisporic and most of 

 them apparently mature. They are rather straight or only a little 

 bent, 140—180 fi long and 45—60 \x broad. 



The conceptacles of sporangia in f. JRosenvingii are stated by 

 Rosenvinge 1. c. to be only about 250 jj. in diameter. I found 

 some few in the above mentioned specimens which are 300 — 350 

 /j. in diameter seen from the surface, but perhaps they are fre- 

 quently smaller, or R o s e n v i n g e's measures may be from median 



