BOTANICAL GAZETTE. m 



are, with woiulorful rapidity. The hot sun of June and July is no hindrance but 

 accelerates the growth ; now rivers, ponds and pools are made green with the abund- 

 ance of many of the more common forms; the sultry weather of August and Septem- 

 ber is favorable to the development of other varieties on moist or shaded grounds, old 

 w'ood, walls, trunks of trees, &c. There is no season until the earth is again covered 

 with snow and the rivers are bound up with thick layers of ice, in which the collector 

 is not richly rewarded in his researches. Specimens are easily preserved. When it 

 can be done they ought to be examined when fresh, but dried and laid aside for years, 

 Ihey may be taken up and examined with profit. I was particularly struck with this 

 fact, recently examining a collection made in part, some ten and tifteen years back. 

 The specimens retained their generic and specific characters well. 



Is variety, delicacy or beauty an object, they are not excelled by the Fungi or Lich- 

 ens, nor by their nearer kin the larger marine plants, that attract so much attention 

 from the lovers of the beautiful; true, they are generally very small ; the eye needs as- 

 sistance and generally a good compound microscope, but the admiration and the won- 

 der excited is none the less. A single drop of carefully collected*pond water will often 

 be found to contain a score or more of smaller forms, all perfect in symmetry, beauti- 

 fully shaded with chlorophyl, or variously tinted with orange-yellow, purple or golden 

 red. So small and yet so perfect; the wonders of the Divine mind are no less evident 

 here than in the greater works of His design. 



But in studying the lite history of these plants the mind is constantly fed with 

 new enjoyments. I cannot forget the first time I observed the "l)irlh of an (Edogon- 

 ium." I had under the microscope a number of filaments of a plant of this genus; I 

 had been studying the form and character of the oogonias and now was taking the pro- 

 portions of the length and breadth of the cells, when I saw two cells separating at the 

 joint, and a sack-like form slightly protruding; it was something new to me; I kei)t 

 my eye on it; it moved very slowly but perceptibly, gradually protruding mcn'e and 

 more; soon it was quite out, distorted in form from the pressure it was subjected to in 

 passing through so narrow a passage ; in less than five minutes more it changed to a 

 perfect sphere, a head became evident in a somewhat raised colorless point Avith two 

 cilia on opposite sides of it, these begin to move, the vibration becomes more ra])id and 

 communicates motion to the new born thing, it oscillates, and olf it darts. In less than 

 fifteen minutes others come to life, and now there are four or five of these "zoospores" 

 darting about in their narrow confines in the field of the microscope. We need not 

 wonder that such men as Ehrenberg and others classified these living spores with the 

 infusoria, they appear to possess volition, how they dart about, but alwajs avoid each 

 other, never collide; the period of their existence is short, in less than half an hour 

 they come to rest, the animal goes back again to the vegetable, they change in foim 

 from spherical lo oblong, then the heads or ciliated ends gradually put forth prong-like 

 projections, these are the rootlets of a new plant which take hold of any suitable sub- 

 stance near by; the jdants elongate by developing cell to cell until we see duplicates of 

 the original mother plant. 



The life history of these plants is full of interest and very important for classifica- 

 tion, and a large field is here open for investigation. 



Have you a desire to make a beginning, where shallyou get specimens ? Are there 

 near by larger or smaller slow streams, or slieltered angles beside more rapid waters, 

 these are sure to contain something, Spirogyra, Cladophora, Mic-rosjioi-a or some other 

 of the common things; or stagnant pools will furnish Qulogonium of some va- 

 riety, Zygnema, Horniospora, i.V;c., or if you have a pond with Ulricularia, or ]\l3'rio- 

 phyllum, gather a (piantity, take it hence and wash it by shaking it well in a bucket of 

 clean water, let it settle, pour ofi'lhe surface until you have a tolerably thick sediment, 

 this will certainly contain some, perhaps very many varieties, of Desmids, beautiful 



