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THE AMERICAN MONTHLY 



J 



etc. In water, Gloeocystis loses its 

 gelatinous structure, and falls to the 

 bottom just as a phaenerogamic plant 

 would do if it were required to de- 

 velop as a swimming plant in river or 

 pond. 



The relations of the algal vegeta- 

 tion to the bottom and to the medium 

 beiiig given, one would necessarily 

 have to seek for the forms of Glceo- 

 cystis, also, those of Gloeocapsa, in ac- 

 cordance with their original habitats, 

 only upon moist bottoms exposed to 

 the air, as upon moss, boards, stones, 

 rock-walls and similar places. It 

 seems strange to me, therefore, to 

 find habitats of another kind, such as 

 ponds, ditches and bog-pools, given 

 in botanical works for Gloeocystis, and 

 certainly, in these instances, the naked 

 conditions of other algae have been 

 confused with Glxocystis. 



There lie before us two articles 

 which greatly enlarge the scope of 

 the genus Gloeocystis, and show close 

 relations with the Volvocinere and the 

 Hydrodictyeae. Cienkowski* found 

 in GltKocystis vesiculosa vacuoles and 

 swarm-spores which, excepting the 

 absence of the pigment-spot, were 

 quite similar to those of Chlamydo- 

 monas, and Lohde \ observed in an 

 undeterm.ined species, after the forma- 

 tion and arrangement of the spores, 

 an affinity with the Hydrodictyeae. 

 Accordingly, we would have three 

 types of Glceocystis to distinguish, one 

 which is related to the Volvocineas, 

 another to the Hydrodictyeae, and a 

 last and most low in organization 

 which corresponds to the Palmellaceae. 



Since I have assumed to regard 

 only the last group, which is only 

 to be found upon moist surfaces ex- 

 posed to the air as Gloeocystis, I 

 must regard the results of the inves- 

 tigations of Cienkowski and Lohde, 

 in themselves of the greatest value, 

 as relating to the Volvocineae, not to 

 Gloeocystis. 



* Bot. Zeit., 1865, No. 3. 



■|- Shenk and Lurssen, Miitheilungen aus 

 dem Gessammtgebiete der Botanik, I Band, 

 p. 478-485. 



Cienkowski has described and 

 figured a Pleiirococcus super bus from 

 a pond ; but in Rabenhorst's Flora 

 Eur op. Alg. Ill, p. 29, this is given 

 as a synonym of Gloeocystis ampla. 

 In the same article Cienkowski has 

 drawn Gloeocystis vesiculosa into the 

 line of the investigation, and figured it 

 to show its great resemblance to 

 Chlamydomonas ; unfortunately, the 

 place where it was found, a con- 

 sideration to which I attach impor- 

 tance, is not stated. It would cer- 

 tainly be unjust to refer it to the 

 same place as the Pleiirococcus super - 

 bus ; but I am not inclined to assume 

 for it the normal habitat, particularly 

 as my many weeks of observation on 

 Gloeocystis from moist rocks, moss- 

 cushions and the like, showed no 

 vacuoles or swarm-spores like Chlamy- 

 domonas, but rather indicated a form- 

 circle of its own. Lohde's Glceocys- 

 tis with a very thin envelope, from the 

 bottom of a glass vessel, and which 

 occurs also in ponds, is apparently a 

 condition of Chlamydornojias, which 

 is known to form different spores 

 under different conditions. 



I was able to cultivate for a long 

 time a Gloeocystis which I collected 

 from moist-boards, rocks and moss, 

 but I have not succeeded in observ- 

 ing spores and swarm-cells. Among 

 freshly collected jelly-masses from 

 rock-walls and moss, with Gl. rzipes- 

 tris, Rab., I often found pale, stellate, 

 and at other times green, spherical, 

 spinous cells with a hard coat, 8-14," 

 in diameter, which I might take for 

 resting-spores ; their true position 

 must, however, remain to be indi- 

 cated by further observation. In 

 other cases my observations have 

 shov/n that Gloeocapsa monoccoca, Ktz., 

 and Gloeocapsa stillicidio?'tim, Ktz., 

 Tab. Phyk., I, f. 20, come together, 

 and are to be placed in the form- 

 circle of Gloeocystis vesiculosa ; further 

 that Palmogloea lurida and rupestris 

 belong to Glceocystis rupestris, Rab. 

 In the Spring of this year I collected 

 from moist boards, Gloeocapsa mono- 

 cocca, Ktz. i^Tab. Phyk., I, f. 23). 



II 



