89 



are rectangular, occasionally nearly squarish, about 10 — 14 /j. long 

 and 6 — 8 /j- thick, with most often rather thick walls. 



The conceptacles of sporangia, which I also found in A re- 

 sell oug's above mentioned type, are more or less densely crowded 

 over the whole frond without any order. I have not seen younger, 

 but fully or nearly fully developed, or emptied ones. They are 

 always immersed, seen from the surface depressed-globular or 

 oblong, not cup-shaped, as in the below mentioned conceptacles, 

 about 100 — 150 /i in diameter, at least towards maturity surrounded 

 by an annular or oblong border, partly rather indistinct, but visible 

 by its a little lighter colour, partly distinct, but not or very slightly 

 raised above the surface of the frond, including this border 200 — 

 300 p- in diameter. The roof is intersected with 20 — 30 muciferous 

 and rather coarse canals, which towards maturity often are about 

 8—10 fj- in diameter. By and by the roof gets nearly dissolved, 

 the surrounding parts continue their growth and the conceptacles 

 become overgrown. Occasionally the whole roof as well as the 

 greater part of the border falls away, leaving a rather deep hole. 

 The tetrasporic sporangia are in general 90 — 110 fi long and 25 — ■ 

 40 or 45 ji broad, by a thickness of about 1 / 2 — 1 / 3 of the breadth. 



Overgrown conceptacles frequently are numerous, spherical or 

 flattened-spherical, about 200 — 300 //. in diameter, and now and 

 then having been filled with local formations of tissue, probably 

 corresponding with the mentioned falling away of the roof and 

 border. 



The conceptacles of cystocarps and antheridia appear to occur 

 in other individuals than those bearing sporangia. Once I have 

 seen them in an individual growing on the same substratum as, 

 and in part confluent with another individual bearing sporangia. 

 However, I am not sure whether the below described organs in- 

 clude the one or other, or, as I am most inclined to suppose, both 

 the named ones. I found them in two small specimens from Mandal 

 and a couple of others from Helgoland, the former kindly sent 

 me by Prof. Wille and the latter by Dr. Kuckuck. 



In the named specimens from Mandal the conceptacles are 

 from the surface of the frond at first visible as globular points 



