130 WAYSIDE AND WOODLAND FERNS. 



indicates the plant's habitat. Quillwort is suggested by the 

 rounded slender form of the leaves. Merlin's-grass may be 

 so called from some real or supposed connection with the prince 

 of enchanters, or with the small species of hawk known as 

 Merlin. 



A word of caution may not be out of place to those readers 

 who have never seen this plant, and who may be seeking for 

 it in our alpine or sub-alpine lakes. There is a flowering plant 

 allied to the Shepherd's Purse and known as the Awhvort 

 (Stibularia aquatica) which is superficially very similar to the 

 Quillwort. As its Latin name indicates, it is found in similar 

 situations to those of the Quillwort, and if care is not taken to 

 examine the leaves a specimen of Awlwort may be taken 

 home in lieu of the desired Quillwort. 



Guernsey Quillwort (Isoetes hystrix). 



This is a much smaller plant than /. lacustris, and its leaves 

 lack the rigidity of those. They are only an inch or two long, 

 and so slender as to appear thread-like, though they have a flat 

 upper surface and a rounded back. The dilated base has three 

 long spine-like teeth, and when the slender portion of the leaf 

 decays the base remains attached to the corm. The general 

 effect of the old leaf-bases with their teeth has suggested the 

 name hystrix, which is Latin for a porcupine. (Plate 142.) 



The sporangia are enveloped by the leaf-base, and are mature 

 in May and June. The megaspores are white. 



This plant is only politically British, our only stations for it 

 being the islands of Guernsey and Alderney, where it occurs 

 not permanently submerged, but growing on sandy or stony 

 ground that is only occasionally inundated. It is also found in 

 the South of Europe and North Africa. 



