30 SELAGINELLACEAE 



2. Selaginella rhoddspora Baker. Plants bright yellowish green, tufted, 1-3 

 cm. long, with short branches 2 mm. broad: leaves of the lower plane 1.75-2 mm. 

 long, .75 mm. broad, obliquely oblong, apiculate, the margins each with 14-18 

 bristle-like teeth: leaves of the upper plane smaller, lanceolate, long-acuminate, with 

 about 7 teeth on each margin: cone 2-5 mm. long: bracts ovate-lanceolate, abruptly 

 long-acuminate, awned, the edges with 15-18 bristles: megaspores reddish orange, 

 about 22 /* in diameter, tubercled. 



On damp edge of lime sinks, in hammocks, southern peninsular Florida. Also in Cuba. 



3. Selaginella Ludoviciana A. Br. Plants dark green, the stems creeping or 

 ascending, 15-30 cm. long, once or twice pinnately branched : leaves in two planes, 

 those of the lower plane broadly ovate, obtuse, with whitish margins formed of 

 sclerotic cells, those of the upper plane lanceolate, slender-tipped: cones 1-2 cm. 

 long: microspores smooth. 



In shaded ground, Florida to Louisiana. 



4. Selaginella arenicola Underw. Stems copiously rooting, much branched, 

 the branches tufted, slender, 5-8 1 cm. tall: leaves appressed, narrowly lanceolate, 

 0.25 mm. wide, ciliate, channeled dorsally, tipped with a spinulose white awn 0.35- 

 0.50 mm. long: cones sharply 4-angled, 2-3 cm. long: bracts broadly lanceolate, 

 spreading, with 15-20 cilia on each side : microspores copious, globose-tetrahedral. 



In exposed sandy fields, Georgia and Florida. 



5. Selaginella Sherwoodii Underw. Stems repeatedly branched, in compact erect 

 or ascending tree-like tufts: leaves about 10-ranked, about 1.5 mm. long, closely ap- 

 pressed, grooved dorsally in the lower two thirds, ending in a slender white coiled hair 

 0.70.9 mm. long, and with 8-12 minute cilia on each margin; cones less than 5 mm. 

 long; bracts similar to the ordinary leaves; megasporanges three-lobed, the megaspores 

 pale yellow, rugose-reticulate, 0.44 mm. in diameter; microsporanges round-reniform, 

 the microspores bright yellow, smooth, 44 /* in diameter. 



On rocks, mountains of southwestern North Carolina. 



6. Selaginella tortipila A. Br. Stems rooting only near the base ; branches zigzag, 

 20-25 cm. long, primary ones elongated. Leaves about 6-ranked, loosely imbricated, 

 narrowly lanceolate, ciliate, scarcely channeled, tipped by a contorted or coiled hair: 

 cones 4-5 mm. long, slightly 4-angled: bracts ovate-lanceolate, dorsally channeled. 



On rocky mountain tops, North Carolina and South Carolina. 



7. Selaginella rupestris (L.) Spring. Stems and branches creeping, 5-10 cm. 

 long, zigzag, ascending at the tips; primary branches short. Leaves closely imbri- 

 cated, about 8-ranked, 0.3-0.38' mm. wide, deeply channeled dorsally, with 6-9 cilia 

 on each side, tipped with a white spinulose awn about 1 mm. long: cones 1-1.5 cm. 

 long, sharply 4-angled: bracts similar to the leaves but broader and with shorter awns 

 and more cilia. 



On dry rocks, Maine and Ontario to British Columbia, south to Georgia and Missouri. 



8. Selaginella acanthonota Underw. Stems and branches stout, rooting and 

 ascending, softly plumose at the tips. Leaves &-10-ranked, about 2 mm. long, gradu- 

 ally tapering into a roughened awn J their length, with about 12 short irregular 

 cilia on each side and similar cilia on either side of the dorsal groove: cones fully 

 1 cm. long: bracts broadly triangular, ciliate. 



In sand, near the coast, North Carolina to Georgia. Summer. 



Order 6. ISOETALES. 



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 ex- 

 cavated bases of the leaves, the sides more or less covered with a fold of the 

 inner side of the leaf -blades (velum) ; those of the outer leaves usually contain 

 spherical, mostly sculptured megaspores, those of the inner contain minute 

 powdery oblong microspores; the former germinate into prothallia bearing only 

 archegones, the latter into prothallia bearing usually only a single antherid. 



FAMILY 1. ISOETACEAE Horan. QUILLWORT FAMILY. 

 Characters of the order. 



