40 



Dansk Botanisk Arkiv, Bd. 3. Nr. 1. 



pedicellate examples 

 also occur. The spor- 

 angia are placed 

 upon the lowermost 

 cells of the branches 

 mostly only two or 

 three upon each fila- 

 ment ; but they also 

 occur upon the main 

 Fig. 36. Acrochsetium opetigenum nov. spec. filaments. 



a, Transverse section of Dasya elegans with basal COLLINS has de- 



parts of three plants two of which fixed to the base -r. Arrorhjp- 



of a pinnule and showing the cuneate endophytic sciiüeu dii Jiuuutai 

 process penetrating into the tissue of the host and tium {A. Dasyæ) also 

 one fixed to the pinnule itself, b, basal part of an pi nn^im 



older vigorous plant showing the endophytic cuneate ^^unu upon jjubya 

 process and further two short epiphytic branchlets ; elegans which seems 

 from that to the kftjn^^erect ^filament is issued, ^osely related to the 



present species. It 

 has for instance the same globular persistent basal spore but this 

 emits, as described by Collins, "a short, descending process, some- 

 times branched, of a few small rounded cells, 

 attached to the host". I have examined the 

 specimens, distributed in Phycotheca Bor. -Am., 

 No. 1342 and have seen these short, 2 — 3 celled 

 branches. As far as I can observe these branches 

 are not endophytic and they are upon the whole 

 quite different to the descending process found 

 in my plant. Besides this difference my species 

 has a very different appearance, is much larger 

 in all parts of the thallus, much more branched 

 and the ramification is not secund. 



Found upon Dasya elegans in a depth of 

 about 20 meters. 



St. Jan: Off Cruz Bay. 



12. Acrochætiuin robustum nov. spec. 



Thallus cæspitosus, usque ad 1 mm longus, 

 e filis erectis et fihs horizontalibus epiphyticis 

 compositus. 



Spora germinans in texturam hospitis pau- 

 lum penetrans ; a superiori parte, non immersa, 

 fila brevia repentia, plus minus lateraliter con- 



Fig. 37. Acrochse- 

 tium opetigenum 

 nov. spec. Sporan- 

 gia-bearing filaments 



with chromato- 

 phores and pyreno- 

 ids. (About 400:1). 



