SELAGINELLA FAMILY. 45 
3. Selaginella apus (L.) Spring. Creeping Selaginella. (Fig. 101. ) 
Lycopodium apodum I, Sp. Pl. 1105. 1753. 
Selaginella apus Spring in Mart. Fl. Bras. 1: 
Part. 2, 119. 1840. 
Annual, light green, stems prostrate- 
creeping, 1/-4’ long, much branched, flac- 
cid, angled on the face. Leaves minute, 
membranous, of 2 kinds, 4-ranked, spread- 
ing in 2 planes; upper leaves of the lower 
plane spreading, the lower reflexed, ovate, 
acute, serrulate, not distinctly ciliate; 
leaves of the upper plane ovate, short-cus- 
pidate ; spikes 3’’-8’’ long, obscurely quad- 
rangular; bracts ovate, acute, sometimes 
serrulate, acutely keeled in the upper half ; 
macrosporanges more abundant toward 
the base of the spike. 
In moist shaded places, often among grass, 
Maine and Ontario to the Northwest Terri- 
tory, south to Florida, Louisiana and Texas. 
Ascends to 2200 ft. in Virginia. July—Sept. 
Family 11. ISOETACEAE. Underw. Native Ferns, 104. 1881. 
QUILLWORT FAMILY. 
Aquatic or marsh plants rooting in the mud, with a short buried 2-lobed or 
3-lobed trunk (stem) sending out abundant roots and sending up a compact tuft 
of rush-like leaves. Sporanges sessile in the axils of the leaves, some containing 
macrospores (macrosporanges), others microspores (microsporanges); the for- 
mer germinate into prothallia bearing only archegones, the latter into prothallia 
bearing usually only a single antherid. 
The family consists of the following genus only. 
1. ISOETES IOs yok JAI, Tatelo, un giG ey 
Submerged, amphibious or uliginous plants with a cluster of elongated awl-shaped leaves 
rising from a more or less 2—3-lobed fleshy short stem, the leaves with or without peripheral 
bast-bundles, with or without stomata, bearing a small membranous organ (ligule) above 
the base. Sporanges sessile in the excavated bases of the leaves, orbicular or ovoid, the 
sides more or less covered with a fold of the inner side of the leaf-base (velum). The 
sporanges of the outer leaves usually contain spherical, mostly sculptured macrospores, 
those of the inner ones contain minute powdery usually oblong microspores. [Name 
Greek, taken from Pliny, apparently referring to the persistent green leaves. ] 
About 50 species, widely distributed. Besides the following 2 are known from the southern 
United States, 7 from the Pacific Coast and 2 from Mexico. Owing to their aquatic habitat and ap- 
parently local distribution, these plants are popularly little known. ‘The spores mature in summer 
and autumn. 
Submerged or rarely emersed in very dry seasons ; leaves quadrangular, without peripheral bast- 
bundles. 
Stomata wanting ; macrospores crested. 
Leaves stout, rigid, scarcely tapering. 1. J. lacustris. 
Leaves slender, tapering. 2. I. Tuckermani, 
Stomata present ; macrospores echinate. 3. I. echinospora, 
fT aca or submerged only in earlier stages; stomata always present on the quadrangular 
eaves. 
Peripheral bast-bundles wanting ; velum partial. 
Leaves 2'-3' long ; macrospores with minute warts. 
Leaves 4-8’ long ; macrospores with jagged crests. 
Peripheral bast-bundles present ; macrospores honeycombed-reticulate. 
Terrestrial ; stomata abundant on the triangular leaves. 
Leaves 15-60, usually black at the base. 7. I. melanopoda. 
Leaves 8-12, bright green, paler at the base. 8. J. Butler, 
. I. saccharata, 
. I. riparia. 
I. Engelmanni, 
Dun 
