. Scottish geographical magazine. a not above 105c C. (51° F.); and Lemna trisuka up to 11° C. Water plants have long been recognised in works on the BritishFlora as hygrophiles, or by Warmings name of hydrophytes. No great BOTANICAL SURVEY OF SCOTLAND. 77 experience amongst them is required to recognise that the hydrophytesare not all equally hydrophytic. Between water plants and land plantsthere is every stage of transition, and every variation in the distributionof water provides conditions suitable for some association of plants. Asa first step in the analysis of this vegetation we may dis
. Scottish geographical magazine. a not above 105c C. (51° F.); and Lemna trisuka up to 11° C. Water plants have long been recognised in works on the BritishFlora as hygrophiles, or by Warmings name of hydrophytes. No great BOTANICAL SURVEY OF SCOTLAND. 77 experience amongst them is required to recognise that the hydrophytesare not all equally hydrophytic. Between water plants and land plantsthere is every stage of transition, and every variation in the distributionof water provides conditions suitable for some association of plants. Asa first step in the analysis of this vegetation we may distinguish thetrue aquatic associations from those of the marsh and bog. The formercan only be developed where there is permanent submergence in and bogs are formed where the substratum alternates betweenlengthened periods of submergence under water, and shorter periods of acondition more or less resembling dry land. These conditions exist inthe basins of streams liable to periodic rise and fall, or in hollows where. Fig. 11. -Methven I h. T1i<j shores are fringed by the tall reed-swamp, seen against the trees. The rush marsh is on the landward side of the reed swamp, and a drier marshyvegetation occupies the foreground. The louli is frequented during the nestingby numerous seagulls, seen in flight. {Photograph by Robert Smith.) water accumulates during a rainy season and is slowly removed byevaporation. Marshes and bogs in Britain occupy soils which arewaterlogged from the commencement of the autumn or winter rains tillthe following summer, and even during the drier season they are liableto frequent shorter periods of flooding and drying. The characteristicfeature of the plants of marsh or bog is that on the one hand their rootsand other parts buried in the substratum show adaptation to a life inwater, while, on the other hand, their aerial parts either resemble thoseof mesophytic land-plants, or they assume the form of reduced leavesand other adaptations suit
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectgeography, bookyear18
