ARCHER ON PALMOGLCEA MACROCOCCA (KI7TZ.). 25 



be seen that the former represent a broadly elliptic, the latter a cylin- 

 'drical form. Indeed, I consider that Eabenhorst's figures said to repre- 

 sent " P. macrococca" seem actually to be copied from De Bary's figures 

 of M. violascens. As to Rabenhorst's description of "P. macrococca," 

 an objection to be made to it seems to be that it is not sufficiently in 

 detail, as the characters given would as well apply to two or three ap- 

 parently distinct species ; nor do the characters agree with the figures 

 (seeing that they represent violaseens). And as to the validity of their 

 distinctions, I would beg observers to suspend their judgment, at least 

 until careful examination be made of the fresh specimens. In regard 

 to the generic characters given by Rabenhorst for Palmogloea, they are 

 intended to include only, and to be restricted to, the forms appertaining 

 to Mesotrenium (Nag.), while Cylindrocystis (Menegh.) is included in 

 Penium (Breb.) But, as I have before pointed out, Cylindrocystis seems 

 sufficiently well characterized as a distinct genus. The statement as to 

 the constant incorporation of cell- wall and contents in the act of conju- 

 gation must be modified as regards Mesotsenium, as will be seen by the 

 description in this paper. 



Of the three species of Mesotsenium described by De Bary, I have 

 above indicated that I believe the P. macrococca could not have been 

 Mesotcenium Braunii (De Bary). The narrow-cylindrical cells with 

 rounded ends seem quite to separate it from the broadly elliptic form, 

 gradually diminishing towards both ends, of M. violascens (De Bary). 



I believe, then, it is more probably with M. chlamydosporum (De 

 Bary) of properly described species, that the identity of P. macrococca 

 exists. 



It is indeed to be regretted that in endeavouring to settle the 

 identity of the plant in question, from the insufficiency of Kiitz- 

 ing's description, we have little else to go upon but the external 

 outline; yet the genus being known, I must hold to the opinion 

 that this is by no means unimportant, and there can be no doubt 

 but that the genus here is Mesotoenium. After some search in our 

 Dublin and Wicklow hills, I have succeeded in finding, and pretty cer- 

 tainly identifying by De Bary's description, his three species of that 

 genus ; and in my opinion M. chlamydosporum is the only one which suits 

 Kutzing's (indeed but vague) description of the debated plant. They 

 are both cylindrical, with rounded ends, and coincide pretty nearly in 

 the measurements, and are common, whilst the gelatinous mass is rather 

 firm — thus agreeing with Kutzing's character in that regard, upon which 

 he lays so much importance. His Palm, protulerans and Palm, micrococca 

 are much smaller plants. I believe I have found here one or both, but 

 I have not as yet been at all able to satisfy myself as to their actual 

 nature. It seems probable that the Coccochloris protuberans (Spreng., 

 Hass.) may be identical with P. macrococca. 



Bat here any farther power of comparison of Kutzing's andBraun's 

 plants ceases, owing to the meagre description of the former. As to the 

 possible identity of any other of Kiitzing's forms with P. macrococca or 

 others, I have hereinbefore ventured to express a conjecture. 



E 



