KONGL. SV. VET. AKADEMIENS HANDLINGAK. BAND. 20. N:() 5. 143 



a hair-shaped organ, sometimes even two from the same articular cell. These or- 

 gans resemble trichogynes so much, that I have explained thera as such. Again, 

 other parts of the frond, which may be of comparatively rather wide extent, are formed 

 exclusively of far shorter, thicker, and more intensely coloured, vertical cell-rows; fig. 

 2. These rows are in general not even half as long as the vegetative ones, being ge- 

 nerally about 100 ,u. in leugth. The horizontal rows supporting theni are also soniewhat 

 difterent from those which give rise to the rows of vegetative cells, their cells being 

 ■longer and richer in endochrome. It cannot well be doubted that in these cells spores 

 are engendered. The figures 4 — 6 show this decidedly. Accordingly, in my opinion, 

 they are cystidia. I have not been able to determine the manner of their development. 

 Two cases seem possible: either they are produced independently of any act of fructi- 

 lication and are subsequently developed into cystidia after the fecnndating substance 

 has been transferred to them from the trichogynes, or else by the fecundation of 

 the trichogynes there are developed from the cell-rows by which these are supported 

 horizontal rows of long cells rich in endochrome, which produce the rows of cj^stidia. 

 I have not observed any organ that might be regarded as intended to transfer the 

 fecnndating substance from the trichogynes to the carpogons. It is possible, however, 

 that the horizontal cell-rows are able to perform this function. 



Mature spores are about 10 ,«. in diameter. Besides these organs I have fonnd 

 other formations of the kind represented in fig. y, the nature of which I cannot decide. 

 They may possibly be young tetraspores that have not yet undergone partition. 



I found this little plant occasionally in very little number on stones covered witli 

 Lithflderma fatiscens. The material at my disposition is slight, and, being dried, it 

 is little fit for a closer examination. If the explanation I have proposed with regard 

 to the different parts be correct, the present plant cannot be referred to any genus 

 of the Squaraariacecu that is known to me. 



Hahitat. I have found this plant attached to Lithoderma fatiscens and to stones 

 within the sublitoral zone on an exposed coast. When collected in the middle of 

 September, it had ripe spores. 



Geogr. Distrib. It is knOwn at present only from one place in the Siborian Sea. 



Localitics: The Siberian Sea: Irka3q5i, scarce. 



Fam. RHODYMENIACE.E (Harv.) J. G. Ag. 



Epicr. p. .307; TiMiv. Erit. Syn. p. VIII; lim. mut. 



Gen. Hydrolapathum (Stackii.) J. G. Ag. 



Epicv. p. 369; Stackii. Tentamen, soc. Rupr. Alg. Och. p. 247; cliar. mut. 



Flydrolapathum sanguineum (L.) Stackh. 

 1. c. Piiciis sangnineus L. Mänt. p. 130. 

 Desrr. Hy<irolapatlium snnguincnm .1. G. An. ). n. p. 370. 



