SELAGINELLACEAE 23 



branches somewhat spreading, linear, with subulate tips : fertile branches erect, 5-8 cm. 

 long, usually twice-forked : cones 15-25 mm. long : bracts ovate, gradually contracted to 

 the subulate tips, toothed. 



In woods, Prince Edward Island to Ontario and Minnesota, south to the mountains of North Caro- 

 lina. Also in Europe and Asia. CHRISTMAS-GREEN. 



FAMILY 2. PSILOTACEAE Pritzel. PSILOTUM FAMILY. 



Perennial slender terrestrial or epiphytic plants. Sporanges sessile in the 

 axils of the leaves, 2-3-celled, opening by valves at the apex. Spores uniform. 



1. PSILOTUM K. Br. 



Terrestrial or sometimes epiphytic. Stem dichotomously forked. Leaves alternate, 

 reduced to scales. Sporanges 3-celled, opening by 3 valves at the apex. Spores mealy, 

 oval or elongated-reniform. 



1. Fsilotum nudum (L. ) Griseb. Stems erect, 20-25 cm. tall, 3-angled at the base, 

 copiously forked above, the ultimate divisions with 3 wing-like angles : leaves remote, 

 awl-like, 1-1.5 mm. long : sporanges in interrupted spikes. [P. triquetrum Sw.] 



In hammocks, South Carolina to Florida. Also in tropical America. 



FAMILY 3. SELAGINELLACEAE Underw. SELAGINELLA FAMILY. 



Terrestrial moss-like annual or perennial plants, with much branched stems. 

 Leaves scale-like, uniform and several-ranked, or of 2 kinds and in 2 planes. 

 Sporanges 1-celled, disposed in 4-sided cones, solitary in the axils of bracts, 

 some containing 4 macrospores (macrosporanges), others containing numerous 

 microspores (microsporanges), which develop into small prothallia, those from 

 the macrospores bearing archegones, those from the microspores antherids. 



1. SELAGINELLA Beauv. 

 Characters of the family. 



Stem-leaves of 2 kinds, spreading in two planes. 



Stems flaccid, creeping ; microspores warty. 1. 8, apus. 



Stems rigid, ascending; microspores smooth. 2. S. Ludovidana. 



Stem-leaves all alike, several-ranked. 

 Stems erect or ascending. 



Cones 2-3 cm. long, slender. 3. S. arenicola. 



Cones 5 mm. long or less, as stout as the diameter of the stem. 4. S. Sherwoodii. 



Stems spreading or creeping. 



Stems rooting only near the base : leaves with tortuous hairs. 5. S. torttpila. 



Stems rooting throughout, usually less than 1 dm. long : cones 10-15 mm. long : 



leaves ending in a slender awn. 



Lips of the dorsal groove of the leaf-blades glabrous. 6. S. rupestris. 



Lips of the dorsal groove of the leaf-blades spinose-ciliate. 7. S. acanthonota. 



1. Selaginella apus (L. ) Spring. Annual, pale green. Stems creeping, 5-15 cm. 

 long, flaccid, pinnately branched : leaves in two planes, those of the lower plane ovate, 

 acute, short-ciliate on the margins, those of the upper plane lanceolate short bristle-pointed : 

 cones 6-15 mm. long, obscurely 4-angled : bracts ovate, acutely keeled above : microspores 

 warty. 



In moist shaded ground, Maine and Ontario to the Northwest Territory, Florida and Texas. 



2. Selaginella Ludoviciana A. Br. Annual, dark green. Stems creeping or ascend- 

 ing, 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 with slender acuminate tips : cones 1-2 cm. long : micro- 

 spores smooth. 



In shaded ground, Florida to Louisiana. 



3. Selaginella arenicola Underw. Boots copious, delicate, 15-20 cm. long. Stems 

 much branched, the branches tufted, slender, 5-8 cm. tall, giving off brown roots near 



... , ', , i , /-v r* r " J 1 * j. "U 1 J 1 



spores copious, globose-tetrahedral. 



In exposed sandy fields, Georgia and Florida. 



4. Selaginella Sherwoodii Underw. Plants forming densely branched compact 

 tree-like tufts 6-8 cm. high. Stems repeatedly branching, erect or ascending, rooting only 

 at the base, rigid ; leaves about 10-ranked, about 1.5 mm. long, closely appressed, grooved 



