38 (A REX STRICTA. TUSSOCK-SEDGE. 



species always attracts by the earliness of its flowers and by the 

 large and peculiar tussocks it forms in low, swampy grounds. 

 These tussocks are generally a foot high and fully as wide, and 

 very often are all the vegetation that exists to any great extent 

 in swampy places. They are very much assisted in their forma- 

 tion by frost. As the mud and water expand by freezing, the 

 sedge-tufts are lifted by the expansion, and the finer particles of 

 mud settle under them in the early thaw. The tussocks, there- 

 fore, do not grow up from the mud as by a stem, but are lifted 

 gradually, and the plant-collector often experiences the truth of 

 this observation to his cost, by finding that they tilt over under 

 his foot, as he steps from one to the other. 



A very interesting fact may be noticed in the tussocks in early 

 spring. On the south side the flowers are perfected often a 

 full week before those on the north side. So little warmth is 

 required to bring them forth that the very small difference in 

 the temperature between the north and the south side of the same 

 plant is enough to make this difference in time. 



Another interesting observation can be made on the develop- 

 ment of the staminate spikes. The stamens burst from their 

 enclosing scales very early in the morning, and by about nine 

 o'clock have opened their anther cells and committed their 

 abundant yellow pollen to the winds. Nothing but dry mem- 

 brane remains to represent the anthers for the rest of the day. 

 This process commences from the upper part of the spike down- 

 wards, and only a few series mature every day. The next, a 

 fresh series, lower down, take their part in this action, and after 

 several days the whole spike has bloomed. 



The precise meaning of the division of sexes — the arrange- 

 ment of female flowers in one head and male flowers in another 

 — is not yet clear to botanists. In these Sedges the pollen-bear- 

 ing or staminate flowers are usually mature at a time when the 

 pistils of the female flowers on the same spike are not in a recep- 

 tive condition, and the fertilization of the flower therefore is 

 more likely to be from the pollen of another flower on the same 



