ABSTRACTS. 



759 



p. 125). — The object of the paper is to preserve as complete a record as 

 possible of the extent, physical characters, and biological relations of the 

 glacial lakes and ponds, since at no very distant day they must disappear 

 if the processes now in operation continue. 



The general change has been from semi-arctic and hydrophytic 

 to temperate and mesophytic conditions. At the same time there has 

 been a continuous reaction of plant life upon environment ; the ad- 

 vancing zones leave soils behind them different from those they found. 

 Sphagnum swamps and peat bogs are the last stages in the life history of 

 glacial lakes. 



The lake selected was a " kettle-hole " in the terminal moraine on the 

 north-west shore of the ancient Lake Maumee. It was formerly much 

 larger, then shrank into two, one nearly having disappeared. It is at 

 present east and west 1,300 feet, and north and south 700 feet. Between 

 the water's edge and the higher ground is a swampy border 10 feet to 

 20 rods wide. The lake basin proper is surrounded by a shallow marginal 

 rim, 40-75 feet in width, descending to 20 feet below the surface. This 

 marginal rim owes its existence to organic factors still at work, the soil 

 being of organic material for several feet in depth. The central area is 

 entirely barren of vegetable life in consequence of the feeble amount 

 of light. 



The plants are grouped into five fairly well-defined zones as follows : 

 — (1) The innermost is a zone of Potamogeton zosterifolius in water 

 from 18 to 6 feet in depth ; it is 30 feet wide. (2) A zone of Nuphar 

 advena, 30-70 feet wide up to the water's edge. (3) A zone of Carcx 

 and Sphagnum from the water's edge to 25 feet. (4) A zone of Salix 

 and Popidus, 10 to 40 feet wide, on soil of almost entirely vegetable 

 origin. It never becomes mesophytic, and is often hydrophytic. (5) A 

 zone of GraminecB and Composites outside the last. It is the transition 

 zone in which mesophytic species begin to mix with hydrophytes ; its 

 landward border merges gradually into the vegetation of the surrounding 

 country. Each of these zones is continually encroaching upon the next 

 inward, as soil increases and the plants can adapt themselves to deeper 

 water. Scirpus lacustris is one of the foremost plants, and Salix rostrata 

 with Betida pumila are among the foremost plants encroaching upon the 

 Carex zone. 



The " dead lake " alluded to has water in the middle in spring-time 

 only. In the centre of the depression there is a group of Sedges and 

 Ferns, which are surrounded by a wide belt of Willows ; outside these is a 

 zone of Grass and other plants. The Sedges have exterminated the water- 

 plants, and now the Willows have all but exterminated the Sedges. 



G. H. 



Hyacinth Culture in the British Isles. (Garden, No. 1,590, 

 p. 297 ; 10/5/1902). — An article on what the writer says " truly should be 

 an important industry in these isles." A sandy, saline soil would appear 

 to be necessary for their proper cultivation, and an account is given of 

 trials in Norfolk, where the soil of the district has been recently, so to 

 speak, reclaimed from the sea. The method of propagation is described, 

 and the writer says : " I feel sure there is a great future for the English 



