26 



THE AMERICAN MONTHLY 



[February, 



etc. In water, Glceocysiis loses its 

 gelatinous structure, and falls to the 

 bottom just as a phsenerogamic 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 

 being 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 Gloeocyslis, and 

 certainly, in these instances, the naked 

 conditions of other alg?e have been 

 confused with Glceocystis. 



There lie before us two articles 

 which greatly enlarge the scope of 

 the genus Glceocystis, and show close 

 relations with the Volvocine?e and the 

 Hydrodictyese. Cienkowski * found 

 in Ghtocystis vesiculosa vacuoles and 

 swarm-spores which, excepting the 

 absence of the pigment-spot, were 

 quite similar to those of Chlamydo- 

 motias, and Lohde f observed in an 

 undeterm.ined species, after the forma- 

 tion and arrangement of the spores, 

 an affinity with the Hydrodictyece. 

 Accordingly, we would have three 

 types of Gloeocystis to distinguish, one 

 which is related to the Volvocinese, 

 another to the Hydrodictyeae, and a 

 last and .most low in organization 

 which corresponds to the Palmellacese. 



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 Glceocystis, I 

 must regard the results of the inves- 

 tigations of Cienkowski and Lohde, 

 in themselves of the greatest value, 

 as relating to the Volvocinese, not to 

 Glceocystis. 



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



\ Shenk and Liirssen, Mittheiltingen aus 

 dem Gessammtgebiete der Boianik, I Band, 

 p. 478-485. 



Cienkowski has described and 

 figured a Flein'ococcus superbus from 

 a pond ; but in Rabenhorst's Flora 

 Eiirop. Alg. Ill, p. 29, this is given 

 as a synonym of Glaocystis ampla. 

 In the same article Cienkowski has 

 drawn Glceocystis vesiculosa into the 

 line of the investigation, and figured it 

 to show its great resemblance to 

 Chlamydomonas j 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 Pleurococcus super- 

 bus ; but I am not inclined to assume 

 for it the normal habitat, particularly 

 as my many weeks of observation on 

 Glceocystis from moist rocks, moss- 

 cushions and the like, showed no 

 vacuoles or swarm-spores like Chlamy- 

 dojjionas, 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 Chla77iydomonas, which 

 is known to form different spores 

 ■ under different conditions. 



I was able to cultivate for a long 

 time a Glceocystis 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. rupes- 

 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 Glceocapsa monoccoca, Ktz., 

 and Glceocapsa stillicidio>'um, Ktz., 

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

 and are to be placed in the form- 

 circle of Glceocystis vesiculosa ; further 

 that Palmoglcea lurida and ritpestris 

 belong to Glceocystis rupestris, Rab. 

 In the Spring of this year I collected 

 from moist boards, Glceocapsa mono- 

 cocca, Ktz. {Tab. Phyk., I, f. 23). 



