1909-10.] Flora of Scottish Lakes. 83 



from the peat, and derived from the disintegration of tlie underlying 

 rock. 



Typha angustifolia, L. V., VII. Of more restricted distribution than 

 the last, but where it does occur it is usually in greater abundance 

 and covers a considerable area of ground (figs. 84 and 8.5). 



Sparganium ramosum, Huds. ( = S. erectutn, L.). "I., II., III.," V., VI., 

 VII. More abundant in Area VII, than elsewhere, chiefly on the rich 

 boggy margins of lowland lochs. Dwarf varieties occur as well as 

 the large normal form. 



Sparganium simplex, Huds. V., VII. In similar situations to the last 

 species, but usually much less abundant. Weak forms with elongated 

 floating leaves also occur, usually in a foot or so of water. The 

 var. longissimum, Fries, occurs sparingly at Loch Fifty. 



Sparganium natans, i. ( = /S*. ct/fiwe, SchnizL). "I.," IV., V., VI., VII. 

 Rather frequent in IV., scarce elsewhere. Chiefly in peaty lochs of 

 moderate elevation (ante, fig. 34). 



Sparganium minimum. Fries. "I.," IV., VI. Generally scarce, and 

 mostly confined to the hill lochs. I have previously remarked (ante, 

 p. 977) upon the variable nature of this genus. It seems to me that 

 the most degenerate form of S. minimum and the most robust 

 condition of S. ramosum are connected by numerous intermediates. 

 Perhaps experimental culture on the riglit lines with S. ramosum 

 would produce all the other forms. 



LEMNACE^. 



Lemna trisulca, L. VII. Rarely found in the lochs, and only in those 

 having a luxuriant marginal vegetation and non-peaty water, well 

 sheltered by trees. It is very abundant in Kilconquhar Loch. 



Lemna minor, L. VII. Remarks same as to the preceding species, 

 but more fre(]uently met with in the lochs. It is a common plant 

 in ditches, etc., in all the Areas below about 500 feet elevation. 



POTAMOGETONACEyE. 



Zannichellia palustris, L., var. brachystemon (Gay). VII. Rare in the 

 lochs as a rule, but extremely abundant in Kilconquhar Loch. 



Potamogeton natans, L. "L, II., III.," IV., V., VI., VII. Abundant 

 everywhere. It seems to me that this plant and its congener P. 

 polygonifolius run into one another somewhat, although the tAvo 

 species can usually be easily distinguished by the characters ex- 

 hibited by leaf, fruit, etc. The typical P. natans is most often 



