3o6 The Irish Naturalist. 



Polygonum avlculare, Linn., ivar. agrestlnum (Jord.)— 

 Dundrum, Co. Down. 



van vulgatum, Syme— Shore, Killough, Co. Down. 



var. arenastrum (Bor.)— Saintfield. A well-defined variety, growing 

 commonly in the channels by roadsides in compact cushions. 



var. rurlvagrum (Jord.)— Fields by shore, Killough, Co, Down. 

 This is also a well-defined variety. It has long narrow leaves and wiry 

 stems, and grows very long among the herbage in cornfields. 



P. Hydroplper, Linn. — This species is very common in this district 

 (Co. Down), in marshes, along roadsides, and in fields and gardens in 

 places where water lies. A fine vigorous form of it appears every year 

 as a weed in a wet spot in my garden at Saintfield, which Mr. Bennett 

 says is the var. densiflorum of Braun. It has much larger flowers than the 

 typical plant, clustered in remarkably dense bunches at intervals along 

 the flowering branch or stem, and in the axils also, the racemes 

 broader and interrupted, not filiform, and sometimes erect ; and varies 

 from P. Hydrojnper, I suppose, in somewhat the same manner as the var. 

 elatiwi, Gren., does from P. Persicaria, though it has not received varietal 

 rank from British botanists. I quote Braun's description (Flora Bot, 

 Zeit.y 1824, p. 108) : — " /3. demiflomm mihi, elatum, spica terminali 

 cylindrica densa, floribusxil alaribus confertis. Distinguished by its 

 higher stem with numerous spreading branches, broad leaves, and very 

 dense, green, pendent perianths. It grows in ditches and sometimes 

 in marshy woods." 



P. maculatum. Trim, and Dyer.— I found this in 1894 growing in 

 marshy fields north of Dundrum, Co. Down, along with P. lapathifolhim. 

 It is a difficult plant to distinguish, and has no doubt been confused 

 with P. Persicaria or P. lapathifolium, its two nearest allies. It is said to be 

 common on the outskirts of London, and in many parts of England. 

 It is a smaller plant than P. lapathifolium, its leaves are white and woolly 

 beneath, not so broad in the middle and attenuated at either end ; its 

 racemes longer, slender, and forming a more compact spike of flowers. 



P. amphlblum, Linn. — When growing on dry land the beautiful 

 floating leaves and whole habit become so changed that it might be 

 considered a different species. This is I suppose the var. terrestre, Leers. 

 I have seen it in flower on the banks of the Closet river, Co. Armagh. 

 It furnishes an interesting example of a plant adapting itself to a different 

 environment, the floating leaves changing to upright ones, and taking 

 upon them a hairy coat when they leave the water. Since the terres- 

 trial form is not permanent in its characters, it has, strictly speaking, no 

 title to be called a variety, but is only a form. 



P. Blstorta, Linn. — Shrubbery, Saintfield ; Graveyard, Knock, Co. 

 Down. I have never seen the Snakeweed truly wild, either in Co. Down 

 or in Westmoreland, where I have gathered it in similar localities. It 

 seems to have a penchant for graveyards and other rich ground near 

 human habitations. At Kendal it is called Easier ledges, as its succulent 

 leaves appear above ground at that season, and, boiled with oatmeal and 

 other ingredients, are made into herb puddings. 



