1. Isoetes butleri Engelm. (Butler's quillwort) Pl. 17a,b; Map 34
Leaves 6–24 cm long, the outer surface of the base white to tan or brown. Velum
covering less than 1/4 of sporangium. Sporangium walls usually with brown
streaks. Sporangia 6–10 mm long, oblong. Megaspores white, mostly 0.45–0.65 mm
in diameter, the surface smooth or with faint tubercles. Microspores grayish
tan, papillose. 2n=22. April–June.
Scattered through the southern half of the state north to Lincoln
County, but absent from the
Mississippi Lowlands Division (Georgia to Texas,
north to Illinois and Kansas). Shallow depressions and ledges of
limestone glades and prairies, less commonly in limey areas of acidic glades
and prairies or along ponds and creeks.
This species usually grows in calcareous or limey soils. It often grows in
shallow depressions or other areas that have standing water in the late winter
and early spring, at which time it produces new leaves. By the end of June when
these areas become hot and dry, the leaves have withered back to the corms for
the year. The leaves can be difficult to distinguish from those of several
monocot species that grow in the same habitats, notably species of Allium,
Juncus, and Eleocharis.