Smith: Notes on the Vegetation of Ponds. 391 



Bog--bean [Menyanthes)^ Water Dropwort {G£nanihe fistulosa)^ 

 Water Horsetail {Equisettim liniosum) and Bur-reed {Spargaiiium 

 sitnplex). The northern end appeared at first sig-ht to be one 

 mass of Bog--bean, but on closer examination the slender stems 

 of the Horsetail and Dropwort were seen to be fairly abundant. 

 The Bog-bean occurred in the water at this end, and also on the 

 marshy shores ; the plants on land were smaller, and the flowers 

 in the water looked so much more tempting that most of us 

 risked wet boots for the rest of the day. Towards the southern 

 end of the pond the Bog-bean became scattered and confined to 

 the margin. The Water Dropwort was almost entirely confined 

 to the northern end. Along both shores Bur-reed was the most 

 abundant plant, but mixed with it were stems of Water Horse- 

 tail and a few plants of Bog-bean. Duckweed was present 

 throughout the whole pond. With the exception of this last, 

 all the plants have roots and stems embedded in the muddy 

 bottom, and from these leafing and flowering shoots are sent 

 up annually. Taken all together they form an aquatic associa- 

 tion, with at least five sub-associations, viz. : {a) Sedge, [b) 

 Water Parsnip, (c) Bur-reed, {d) Water Horsetail, {e) Water 

 Dropwort and Bog-bean. The last-named three, however, are 

 not well-defined and merge into one another. To explain why 

 these occupy the position they do would require careful 

 investigation. One or two points regarding the life of these 

 pond-plants are, however, fairly evident. The Sedges at the 

 outflow^ end occupy the area where fine mud will be deposited at 

 the sill of the outflow channel ; the water is never more than 

 shallow here, and it is probable that in dry seasons the Sedges 

 are left on wet mud. The Bog-bean is also most abundant near 

 the margin, which in drought will be reduced to marsh. The 

 Bur-reed zone may also become wet marsh. That water does 

 not often disappear from the centre is indicated by the Water 

 Parsnip, which is rarely found except in water. Altogether one 

 might deduce that this pond is not subject to rapid drainage and 

 that it retains water even in drought. 



Fig. 2. — This pond was also full of water, but differs from 

 Fig. I in that it is completely filled with vegetation. At the 

 southern end an inflow is shown, which was bringing in water 

 when we saw it. From the appearance of the channel, it does 

 not always convey water, and only acts as an overflow to some 

 other pond in the same trough. At the northern end there is 

 an outflow depression, which acts as an overflow channel to this 

 pond. The water is probably derived from surface drainage, 



1903 October i. 



