LYCOPODIACEAE (CLUB MOSS FAMILY) 55 



a. Spore cases in the axils of ordinary dark-green shining leaves, not form- 

 ing a well marked terminal spike ; gemmae commonly present. 



Leaves uniform 1. L. Selago. 



Leaves in zones, alternately shorter and longer 2. L. lucidulum. 



a. Spore cases only in the axils of the upper (bracteal) leaves, forming a 



spike b. 

 b. Bracteal leaves scarcely or not at all modified in form or texture. 



Bracteal leaves lance-linear or linear, scarcely broader at the base . 8. L. alopecuroidea. 

 Bracteal leaves linear-attenuate from a distinctly broadened ovate 



base 4. L. inimdatwm. 



b. Bracteal leaves scale-like, yellowish, very different from those of the 



sterile parts of the stem c. 

 c. Sterile branches convex and uniformly leafy on all sides. 



Free part of leaves 4-8 mm. long ; fertile branches mostly 1.5- 



2.5 dm. high. 



Fertile branches leafy up to the spikes. 

 Creeping stem deep in the ground, the upright branches 



repeatedly forked, tree-like . . . (7) Z. obscurum, v. dendroideitm, 

 Creeping stem on or near the surface of the ground, its 

 numerous erect branches mostly subsimple or sparingly 



forked 5. L. annolinum, 



Fertile branches modified beneath the spikes into scaly pe- 

 duncles 6. L. clavatwm, 



Free parts of the leaves 1-3 mm. long ; fertile branches usually 



5-18 cm. high 8. L. sitchense. 



c. Sterile branches flattened or concave beneath, the leaves usually 



reduced or modified on the lower surface d. 



d. Fertile branches leafy essentially to the spikes . . . 7. L. obscurum. 



d. Spikes borne on scaly peduncles e. 



e. Peduncles terminating upright leafy branches. 

 Fertile branches usually 5-10, rarely 



y 5-10, rarely 15 cm. high ; free part 

 of lateral leaves linear-subulate, spreading, nearly or quite 



as long as the adnate part 9. L. sabinaefolium. 



Fertile branches usually 1.5-3 drn. high ; free part of lateral 

 leaves deltoid-subulate, scarcely more than one third to 

 one half the length of the adnate part. 

 Eunning stems deep in the ground; branches narrowly 

 linear, 1.3-1.8 mm. broad, their divisions very numer- 

 ous and crowded 12. L. t/ristach/ywrn-. 



Eunning stems at or near the surface of the ground ; 

 branches 2^4 mm. broad, more loosely and openly 



forked 11. L. complanatum. 



. Peduncles springing directly from a short horizontal rootstock 10. L. carolinianum. 



1. L. Selago L. Stems erect and rigid, dichotomous, from a short slender 

 rootstock, forming a level-topped tuft (0.5-2.5 dm. high) ; leaves uniform, 

 lance-attenuate, crowded, ascending, glossy, pale green or yellowish, sharp- 

 pointed, entire or denticulate ; sporangia in the axils of unaltered leaves. 

 Crevices of exposed or cold rock, chiefly alpine ; Greenl. to Alaska, s. to N. E., 

 L. Superior, Mont., and Wash., and on the higher Alleghenies to Va. (Widely 

 distr.) Commonly gemmiparous in the upper axils. Var. APPRESSUM Desv. 

 Leaves closely crowded, appressed. Usually more abundant, extending s. to 

 N. C. 



Var. patens (Beauv.) Desv. Leaves linear-attenuate and wide-spreading, 

 dark green. Cool calcareous cliffs, Que. and n. Vt. 



2. L. lucidulum Michx. Stems assurgent, the old elongate bases very per- 

 sistent; leaves pointed, toothed, at first spreading, then deflexed, distinctly 

 broader above the middle, arranged in alternate zones of shorter and longer 

 leaves, the shorter leaves more frequently bearing sporangia in their axils ; 

 proliferous gemmae usually abundant but caducous. Cold, damp woods ; Nfd. 

 to Ont., Minn., la., Ind., and south w. in the Alleghenies to S. C. 



Var. por6philum (Lloyd & Underw.) Clute. Leaves lance-linear, attenuate, 

 narrowed from base to apex, nearly or quite entire. (L. porophilum Lloyd & 

 Underw.) Mts. and cold ravines, local ; Nfd. and e. Que. to Wise., s. to S. C. 

 and Ala. 



3. L. alopecuroides L. fitems stout, very densely leafy th 1 . oughout ; the 

 sterile branches recurved-procumbent and creeping ; the fertile of the same 

 thickness, 13-33 cm. high ; leaves narrowly linear-awl-shaped, spinulose-pointed, 

 spreading, conspicuously bristle-toothed below the middle ; those of the cylindri- 

 cal spike with lny setaceous tips. (L. adpressum Lloyd & Underw., in 



