26 HENRIK PRINTZ [1920 



is no doubt very rare in Ihls alga. Though I have observed the 

 species in several samples, in many of which il has occurred in 

 abundance, I have foiuid ai)kmospares in a single only. Neilher 

 have thcy ever been founcl l)y anyone else belore. 



With regand to the systemalical position of Ibis alga, it can, as 

 previously nientioned, on account of ils reproduclion, hardly be 

 referred to the Trentepohliaceae, which, by the way, as lo reproduc- 

 Live organs, form a homogeneous and well def ined family. In ils apla- 

 nospores, on the contrary, it exihibiits resemblance lo the Wittrockiel- 

 laceae. In the slructure of the vegetative thailus it differs from 

 both the families mentiioned. It is as yet uncertain whether this 

 species also has motile sporas, though it must be considered impro- 

 bable. Akinetes, which occur both in the Trentepohliaceae and the 

 VV ittrockiellaceae, I have not been able to point out in Physolinum, 

 as seitae are also entirely lacking. In many ways it seenis to be inter- 

 mediate between the families mentioned, most likely represenling 

 an entirely new family, but this I will leave unsettled until the 

 development and slructure of this peculiar alga is better Iviiown. 



The species is ratlier comimon in many of the samples from the 

 environs of Durban, but I have not found it in anv sample from 

 Sa.danha Bay (nos. 30, 57, 105, 120, 122, 134, 154, 169, 214, 238, 260, 

 261, and 295). 



Trentepohlia aurea (L.)Martius forum. [PI. VU and VIII, Fig. 



244— 263J. 



To begin wilh I was much m doubt whether il would be right to 

 refer the species of Trentepohlia, drawn in the piales VII and VIII, 

 fig. 244 — 203 to Trentepohlia aurea or to Tr. abietina. The real dif- 

 ference between these two species, by the way, seems to me, to be 

 so slight Ihat it may be dubious wheither it is oorrect to maintain 

 Tr. abietina as a species different from Tr. aurea. The vanious 

 aulhors agree thai they are nearly allied, but the views as to where 

 the lines between them should be dra\\'n, on the oither hiand, s&em 

 to be very vague and varying. 



An attempt at drawing a line between the two species, on the 

 basis of the existing lilerature, will show thai much unoertainty is 

 neigning. Let me state some inslanoes: De Wildeman (Les Tren- 

 tepohlia des Ind-Neerland, 1890), for instance, attaches nmch 

 importance to the faet thai one (Tr. aurea) is said to have cyllndric 

 oells, while those of Tr. abietina are more inflated and ellipitic. The 

 last mentioned species iiS said, however, to constilute a transition 

 heflween these two groups, as it miay sometimes be found with 

 rectangular (cylindric)cells. Hariot (Noles sur le Genre Trentepoh- 

 lia, 1889—90), on the other band, refers both species to the one 

 group of the species of Trentepohlia, being distinguished by «cellulae 

 cylindricae». This character is, accordingly, very doulDitful, and 



