A WORD KOBE OB IHI "AGUE TLANT." 1G7 



called daughter-cells, dne to the breaking up of the contents of 

 the original individual, and destined themselres to produce young 

 plants " in the following Bpring" (and to perpetuate the " ague " ?). 

 Indeed, the examination with a hand lens showed certain of the 

 examples which bad burst at the top rilled with these rounded 

 germs (like so many little eggs in a nest). 



I would at once have communicated to the Editor the result of 

 my examination, but that I had Been a reference to a paper pub- 

 lished in the Regensburg "Flora" of 1868, purporting to contain 

 a demonstration by Dr. Ltzigsohn that Hydrogastrum after all 

 was not an Alga, but a Lichen, or at least that its nature was de- 

 bateable, as one was to gather from the title: " Botrydium 

 argillaceum, Wallr., ob Alge oder Flechte?" and I desired to 

 know what ltzigsohn had to say upon our plant, ere sending for- 

 ward a note of what the " Ague Plant" had turned out to be. It 

 will be borne in mind that Itzigsohn's statements could scarcely 

 have had any reference to the new views as to the nature of 

 Lichens propounded by Prof. Schwendener, lately discussed at 

 considerable length, a resume of which has appeared, and is being 

 continued, in the " Quarterly Journal of Micros. Science." But 

 the " Flora" was not then, and has only lately been, available in 

 Dublin. 



From his paper (1. c, p. 129), we are to gather that, the Hydro- 

 gastrum being so common in his region, Dr. ltzigsohn had long 

 looked rather down upon it on that account, and had taken its 

 structure for granted, by, as he mentions, merely squeezing the 

 examples out upon a slide, in place of making sections ; still the 

 examination he had previously given had shown him the formation 

 of zoospores, his record of which is quoted, by Eabenhorst in his 

 " Flora Europasa Algarum Aquae dulcis," etc. (p. 2G5), and which 

 seems to be confirmed by Parfitt (1. c). It would seem, indeed, 

 for so far ltzigsohn had this very plant in view, and that his fore- 

 going statements about it are correct. 



But Dr. ltzigsohn desired to repeat his previous observation as 

 to the occurrence of zoospores in Hydrogastrum, and having re- 

 ceived some examples of what he supposed to be this plant from 

 Dr. Ivuthe, obtained from another locality, he submitted them to 

 examination. He now made vertical sections, and of these he 

 gives a description, but no figures, promising a more enlarged 

 account on a future occasion ; but I am not aware if he ever ful- 

 filled that intention. From that description it appears indeed 

 abundantly manifest it was now not Hydrogastrum at all which he 

 had before him, but a true lichen, though from an outward resem- 

 blance he at once conies to the conclusion that Hydrogastrum 

 (Botrydium) must be no longer accounted an alga, but a lichen. A 

 vertical section through the rounded plant itself indeed gave him 

 an outward cortical or epidermoidal layer, composed of very delicate, 

 distinctly organised rotundato — G-angular parenchymatous cells, 



