



LYCOPODIACEAE 21 



lines of tubercles, the central cavity large, from one-half to two-thirds the diameter ; 

 sheaths rather long, cylindric, marked with one or two black girdles, their ridges obscurely 

 4-keeled ; teeth brown, membranous, soon deciduous : stem rarely producing branches 

 which are usually short and occasionally fertile, sometimes with longer sterile branches. 



In wet places, especially on river banks, widely distributed in North America, Europe and Asia. 

 SCOURING RUSH. 



4. Equisetum laevigatum A. Br. Stems 3-15 dm. high, simple or little branched, 

 pale green, persistent, 14-30-furrowed, the ridges almost smooth. Sheaths elongated and 

 enlarged upward, with a black girdle at the base of the mostly deciduous, white-margined 

 teeth and rarely also at their bases ; ridges of the sheath with a faint central carina and 

 sometimes with faint short lateral ones : stomata arranged in single series ; central cavity 

 very large, the wall of the stem very thin. 



Along streams, especially in clay soil, New Jersey to British Columbia, south to North Carolina, 

 Louisiana and California. 



Order 5. LYCOPODIALES. 



Terrestrial or epiphytic plants with spores produced in sporanges borne in 

 the axils of scale-like leaves. 



Spores all of one sort and size. 



Sporanges 1-celled, transversely 2-valved : stems leafy. Fam. 1. LYCOPODIACEAE. 



Sporanges 2-3-celled, opening by 2-3 apical valves : stems and branches 



nearly naked. Fam. 2. PSILOTACBAE. 



Spores of two sizes, macrospores and microspores. Fam. 3. SELAGINELLACEAE. 



FAMILY 1. LYCOPODIACEAE Michx. CLUB-MOSS FAMILY. 

 Moss-like plants, with erect, trailing or creeping stems. Leaves often nu- 

 merous, in 2-several series : blades narrow. Sporanges 1-celled, solitary in the 

 axils of leaf-like or scale-like bracts (sporophylls), sometimes forming compact 

 cones (strobiles). Spores uniform, minute. Prothallia (as far as known) mon- 

 oecious, mostly subterranean. 



1. LYCOPODIUM L. 1 



Perennial evergreen plants various in habit. Leaves in 4-16 series : blades 1-nerved. 

 Sporanges 1-celled, in the axils of more or less distant leaf-like bracts or collected into ter- 

 minal compact bracted cones, transversely 2-valved. Spores of one kind, sulphur-yellow, 

 copious, readily inflammable. Some species are known as CLUB-MOSSES. 



Plants with mostly upright stems : leaves and bracts (sporophylls) in alternating zones (cones inter- 

 rupted). 



Leaf-blades appressed. with hollow bases. 1. L. Selago. 



Leaf-blades ultimately reflexed, flattened at the bases. 



Leaf-blades linear or nearly so, entire or denticulate. 2. L. porophilum. 



Leaf-blades manifestly broadest above the middle, erose. 3. L. lucidulum. 



Plants with creeping or horizontal stems (rootstocks): cones terminal. 

 Sporanges globose : bracts and leaves similar. 



Bracts 5-6 mm. long, often slightly toothed at the base. 4. L. Chapmani. 



Bracts 8-10 mru. long, usually much toothed. 



Leaves in many series, radially spreading: stems arching. 5. L. alopecurmdes. 



Leaves twisted so as to be in one plane : stems prostrate. 6. L. pinnatum. 



Sporanges transversely compressed, reniform : bracts entirely unlike the leaves. 



Stems (rootstocks) prostrate or creeping : leaves nearly in one plane. 7. L. Carolinianum. 



Stems (rootstocks) creeping or horizontal, with erect or ascending branches. 

 Leaves equal, radially arranged (except on twigs of No. 8), in 5 or more series. 



Cones few, stout, erect. 8. L. obscurum. 



Cones numerous, short, nodding. 9. L. cernuum. 



Leaves dorsiventrally arranged in 4 series on flattened stems. 



Leaves of under row scarcely reduced : terminal branches erect. 10. L. tnstachyum. 



Leaves of under row reduced to subulate scales : terminal branches 



horizontally fan-like. 11. L. complanatum. 



1. Lycopodium Selago L. Prostrate portion of the stems very short, rooting, curv- 

 ing upward, thence dichotomously branched and forming tufts 4-17 cm. tall. Leaves densely 

 disposed, appressed or ascending; blades triangular, linear-subulate or subulate, 4-8 mm. 

 long, broadest at the hollow base, entire : bracts shorter than the leaves, triangular : 

 sporanges reniform. 



On rocks and shaded cliffs, Labrador, Greenland and Alaska, south to Maine, Michigan and Wash- 

 ington and on the mountains to North Carolina. Also in Europe and Asia. 



2. Lycopodium porophilum Lloyd & Underw. Prostrate portion of the stems short, 

 abundantly rooting, curving upward, thence forking 1-3 times and forming tufts 4-10 cm. 

 tall. Leaves densely disposed, spreading or reflexed ; blades very slightly broadened 



1 Revised by Prof. Francis Ernest Lloyd. 



