1911-12.] BOTANICAL SOCIETY OF EDINBURGH 27 



European floras (mainly under Alisma). Neither do 

 Ascherson and Graebner, in their review of these genera, 

 account for many named varieties. 



The following experience will show the sequence of a 

 species of aquatic (Damasonium Alisma, Mill.) that does 

 not reach Scotland, but which I watched through the 

 summer of 1887 on a common (Mitcham) near here. It 

 had then several ponds, many ditches, and swampy places 

 on a gravelly soil. In one pond (since filled up) the above 

 plant grew pretty abundantly. In April it was the form 

 gra mini folium, Gliick; in May it began to make itself 

 into the form spathulatum, Gliick ; at the end of June it 

 had become the form natans, Gliick; flowered through 

 July and part of August; at the end of August the water 

 became very low, and the plant here and there became 

 stranded ; it was now the form terrestre, Gliick. The only 

 one I could not say I saw was the form pumila, Gliick. 

 which he describes as "misera forma terrestris semiue 

 nata, etc." 



The figure in " Eng. Botany," t. 1615 (3rd ed., t. 1442), 

 shows a state between Gliick's natans and terrestris. In 

 the description no mention is made of any other leaves 

 than the cordate floating ones. The plants noted were 

 simply the growth and evolution of the species, influenced 

 by warmth and depth of water. Certainly in July and 

 August, when gathering this in other parts of Surrey, only 

 the form natans could be seen on the water surface; but 

 carefully working in the mud, the form graminifolius was 

 found, probably the result of last year's seeding. Syme 

 in " Eng. Botany " queries it as a perennial ; Hooker and 

 Babington are silent on this point. Bentham calls it an 

 annual. Grenier and Godron ' call it perennial, and 

 Ascherson and Graebner 2 also. My own opinion is that 

 it is neither, but a biennial, as I never was able to find 

 any stolons as in Hydrocharis or Alisma; and the seeds 

 evidently drop off, sink (they sink at once when ripe !), and 

 in winter or early spring form the little tufts found in July 

 with grass-like leaves. 



1 '-Flora France," iii. (1855), p. 167. 



2 "Syn. Fl. Mitteleurop." i. (1897), p. 389. 



