Isoetaceaee Quillwort Family. 
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Perennial grass-like plants of submerged, amphibious or terrestrial 
habit, arising from a shallow woody 2- or 3-lobed corm, bearing a tuft of 
erect or recurved grass-like leaves. Leaves producing a small triangular 
outgrowth or flap of tissue (the ligule) above the single round or oblong 
axillary sporangium which is set in a basal depression of the leaf, the 
sporangium more or less covered by a membranous extension of tissue (the 
velum) on inner leaf face. Sporangia solitary, sessile in axils of leaves, ; 
and somewhat distending them, of two kinds, microsporangia, bearing micro- 4 
spores, minute, powdery, ovoid, which on germination, produce antheridial i 
gametophytes, and megasporangia, bearing megaspores, characteristically 
hemispherical, larger, which on germination, produce archegonial gametophytes, | 
|. Isoetes Le Quillwort,. 
Characters of the family. 
