SELAGINELLACEAE 29 



10. Lycopodlum complanatum L. Horizontal stems wide-creeping along the 

 ground, flattish above, with many erect irregularly forked aerial stems, the branches 

 of these broadly flattened, 2-3-forked, the divisions few, or often numerous and fan- 

 like, leafy throughout. Leaves 4-ranked, minute and (excepting those of the under 

 row) imbricated and decurrent, those of the upper row narrow and incurved, of the 

 lateral rows broad, with spreading tips, and of the under row triangular-cuspidate, 

 spreading: peduncles slender, 2-13 cm. long, bracteate, simple to twice-dichotomous: 

 spikes slender, cylindric, averaging 2 cm. long: sporophyls broadly ovate, acuminate. 



In woods, Labrador to Alaska, south to Idaho, Minnesota and the mountains of North 

 Carolina. Christmas-green. 



11. Lycopodium tristdchyum Pursh. Horizontal stems widely creeping, 2-10 

 cm. below the surface, terete, with numerous erect or assurgent much-forked aerial 

 stems, the branches of these narrow, flattish, with very numerous crowded erect 

 divisions, the ultimate ones leafy throughout. Leaves 4-ranked, minute, imbricated, 

 appressed, strongly decurrent, nearly equal and alike, those of the lateral rows a 

 little thicker, with the tips usually incurved downward: peduncles 7-13 cm. long, 

 bracteate, usually twice-dichotomous at the summit : spike and sporophyls similar to 

 those of the preceding. [L. Chamaecyparissus A. Br.] 



In dryish open woods or clearings, usually in sandy soil, Maine to Minnesota and 

 Georgia. Also in Europe. 



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 R. Br. 



Terrestrial or sometimes epiphytic. Stem dichotomously forked. Leaves alter- 

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

 mealy, oval or elongated-reniform. 



1. Psilotum 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. Selagikella 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, solitaiy in the axils of bracts, 

 some containing- 4 megaspores (megasporanges), others containing numerous 

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

 the megaspores 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. 



Plants pale green: cones 6-15 mm. long. 1. 5. apus. 



Plants yellowish green: cones 2-5 mm. long. 2. S. rhodospora. 



Stems rigid, ascending. 3. S. Ludoviciana. 



Stem-leaves all alike, several-ranked. 

 Stems erect or ascending. 



Cones 2-3 cm. long, slender. 4. S. arenicola. 



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



Stems spreading or creeping. 



Stems rooting only near the base: leaves with tortuous hairs. 6. S. tortipila. 



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. 7. S. rupestris. 



Lips of the dorsal groove of the leaf-blades spinose-ciliate. 8. S. acanthonota. 



1. Selaginella apus (L.) Spring. Plants pale green, the 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 lanceolate, short bristle- 

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



In moist shaded ground, Maine to British Columbia, Florida and Texas. 



