BOTANICAL GAZETTE. 
Yol. 3. JANUARY, 1878. No. 1. 
The Species of Isoetes of the Indian Territory.—Isoetes melanopoda, J. 
Gay, originally found in central and northern Illinois, then in the neighboring re¬ 
gions of Iowa, seems to be peculiar to a belt of prairie country extending from north¬ 
east to southwest, from Illinois to Iowa, the Indian Territory and Texas. Mr. E. Hall, 
who discovered the species in. Illinois, found it also some years ago in Dallas county, 
Texas, and now Mr. G. D. Butler sends it from the Indian Territory. However the 
other characters may vary, the macrospores every where readily-characterize the plant. 
They are the smallest of any of our species, but varying in the same sporangium, be¬ 
tween 0.25 and 0.35 mm., very rarely as much as 0.40 mm. in diameter, marked with 
confluent knobs and curved and twisted (worm-like,) low, sometimes almost indistinct, 
elevations, visible, of course, onl> under a strong magnifier. The velum or membrana¬ 
ceous fold, which more or less completely covers the spore case, or is, rarely, wanting, 
is in this species usually narrow, or sometimes wider; in the southern forms it covers 
about one-third of the upper half of the sporangium. Full-grown specimens are %-l 
inch in diameter at the almost always black and shining base of the leaves; these, 
smaller and fewer in the northern forms, are in. the southern ones 20-50 in number 
and 8-12 inches in length, and, as I have described them in Gray’s Manual, triangular, 
with 4 peripherical fibrous, bundles and with numerous stomata. 
Isoetes Butleri, n. sp .—I name an allied species discovered by Mr. Butler, near 
the latter, in drier soil, a much smaller plant with earlier (beginning of June) ma¬ 
turity. It is at once recognized by its larger macrospores, 0.50-0.63 mm. in diameter,, 
marked with distinct knobs or warts, which rarely run together. The base of the plant 
is only % inch thick, the slender leaves with dull whitish bases, only 8-12' in number, 
are 3-6 or 7 inches long, of exactly the same structure as those of the last species. 
Velum very narrow or almost none. Microspores aculeolate in both, in the latter 
species a little larger than in the former. 
The species of Isoetes are usually,' as is well known, monoecious, the exterior 
sporangia bearing female or macrospores, the interior, later developing ones, male or 
microspores. But I. melanopoda is oftener dioecious than monoecious. Mr. Butler ex¬ 
amined hundreds of specimens and found about one-third monoecious and two-thirds 
dioecious, and of these the male and female plants in about equal numbers. Of Isoetes 
Butleri he never could find a monoecious plant; all the specimens which he found as 
well as those which I examined, were dioecious, both sexes in about equal numbers.— 
G. Engelmann, St. Louis , Nor. 1877. 
To the foregoing description by Dr. Engelmann I append some remarks in regard 
to the loeality in which these plants occur. Both were found near Limestone Gap on 
the Missouri, Kansas & Texas railroad, about 70 miles north and 100 miles west of the 
Texas and Arkansas boundaries, near the divide between the Red and Arkansas rivers. 
The surface of the country is very rough, woods and prairies alternating and of about 
equal extent. There is a clay underlying most of the country. Many wells and 
springs running into or passing through this clay are damaged or sometimes rendered 
unfit for use by the quantities of the sulphates of magnesia and soda, entering into 
solution therefrom. Occasionally this clay arises to the surface, forming low, level 
places, which are. popularly known as alkaline flats, but which I call “sulphate flats,” 
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