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THE BRITISH PEPPERWORTS. 



THE group of plants to which the name of Pepperworts has 

 been given, is technically called Marsileac&z, and contains 

 but a few genera, these being of very curious structure. It 

 has only two representatives in the British flora. These two 

 plants belong to different genera, and are both submerged 

 aquatic plants of small size, agreeing in having grassy or 

 quill-like foliage, but differing materially in habit, the one 

 being a creeping grower and the other tufted; the fruc- 

 tification also presenting some material differences. Isoetes 

 is sometimes classed with the Club -mosses instead of the 

 Pepperworts. 



Genus XX. ISOETES. 



Isoetes, which takes its scientific name from the Greek 

 words isos, equal, and etos, the year, from its retaining its 

 fronds throughout the year, is commonly called Quillwort. 

 The genus differs from Pilularia, its nearest ally, and with 

 which it is associated in the order of Pepperworts, in having 



