270 TRANSACTIONS OF THE [Sess. lxxv 



leaves, reduced flowers, weak stem, and superficial chloro 

 phyll-cells, exhibits some of the salient features of 

 aquatic plants. Littorella lacustris, Linn., is another plant 

 of the lochan, producing its short, awl-shaped leaves beneath 

 the water, while the wind-pollinated flowers with their 

 long stamens appear when the water recedes in dry summer 

 weather. 



On the hilltops small tarns with a peaty substratum 

 are occupied by submerged masses of Sphagnum cuspi- 

 datum, Ehrh., and Amblystegium fluitans, De Not. 

 Another aquatic moss, Hypnum rusciforme, Weis.. occurs 

 on rocks in running water, while in most pools and ditches, 

 and slowly flowing rills, green algse are to be found. 



The only other situation for fresh-water aquatics is an 

 artificial pond in the policies, constructed to maintain a 

 supply of water for working a sawmill. Littorella 

 lacustris, Linn., is again plentiful here, forming a sub- 

 merged turf around the margin of the pond. Occupying 

 an intermediate position, as regards aquatic habit, between 

 this species and the meadow plants on the banks, is 

 Caltha palustris, Linn., growing at the water's edge, or 

 even within it, but witli aerial shoots above the surface. 

 Rooted in the mud at the bottom of the pond, with ribbon- 

 leaves floating on the surface, is Sparganium natans, 

 Linn., solitary representative in all the countryside of 

 the order to which it belongs, showing in the large air- 

 spaces and mucilaginous character of its leaves other 

 typical hydrophytic features. 



6. Marine Vegetation. 



Although not exposed to wave action equal to that of 

 the open sea, the shore at the mouth of Loch Striven can 

 nevertheless not be called a sheltered one, and considerable 

 damao-e has been done to a couple of miles of the coast-line 

 from the mouth of the Loch upwards, during coincident 

 storms and high tides of the winter of 1912-13. Further 

 up the loch the wave action is naturally less, but the steep 

 hills with intersecting glens on both sides of the loch 

 render it subject to sudden squalls. The greatest depth of 

 the loch is 41 fathoms, and the rise of the tide at spring 

 tides is about 10 feet. 



