^^P'-'l Sutton, Growth of the Sea Tassel. 6q 



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ON THE GROWTH, &c., OF THE SEA TASSEL, RUPPIA 

 MARITIMA, Linn. 



By C. S. Sutton, M.B., B.S. 



At Easter, 1914, some dry mud was brought from Phillip Island 

 for examination for crustacean life and placed by Mr. J. Searle 

 in a bottle with water on a shelf at his business premises. 

 Two years later a plant with slender, filiform stems and leaves, 

 which had been noticed growing from the mud, showed signs 

 of flowering. Developments were carefully observed and noted 

 by Mr. Searle until the completion of the seasonal cycle of the 

 plant when he concluded it was Ruppia maritima, or Sea 

 Tassel, belonging to the Naiadacese, or Fluviales, an inhabitant 

 of brackish and salt water in temperate and sub-tropical 

 regions throughout the world. Although urged to do so, Mr. 

 Searle would not directly communicate his most interesting 

 notes, but handed them to me, suggesting I should give them 

 instead. Thinking this might be better done after I had 

 myself continuously observed the plant under more favourable 

 conditions, Mr. Searle gave me a portion, which I planted in 

 sand in a flat glass tank filled with fresh water. 



The following description of the interesting performances of 

 the Ruppia, is then, really a relation of what Mr. Searle 

 previously noted and what I have confirmed by my own 

 observations. The stems of the plant arise from a creeping 

 rhizome, and are slender, filiform, finely-grooved, and very long, 

 lying at length on the surface of the water, but not projecting 

 above it. At the beginning of October, about six weeks 

 earlier than in the previous season (perhaps on account 

 of the more favourable conditions as to light and heat), flower- 

 spikes were noticed developing apparently within the thickness 

 of the stems, which were dilated just above certain of the nodes. 

 These spikes, as they increased in size, separated the leaves 

 nearest to the nodes, showing them to be axillary, transparent 

 sheaths from base of leaf and stem remaining, through which 

 the spikes and their commencing stalks could be now more 

 plainly seen. (Fig. i.) The stalks or peduncles quickly length- 

 ened, eventually somewhat abruptly bringing the spikes to the 

 surface, or even projecting them some distance above it, where 

 they finally lay. The spike appeared to consist of two flowers, 

 each of four anthers or pollen sacs in superimposed pairs, with 

 the carpels clustered on one side of the rhachis between the 

 four lower and on the opposite side between the four upper 

 anthers. The latter were kidney-shaped and of a brownish- 

 green, with light green bands. Viewed from the side, the spikes 

 appeared to consist of four superimposed cassock-shaped 



