1 38 OUR NATIVE FERNS AND THEIR ALLIES. 



shorter and more rigid, pointed leaves are var. pungens Desv. 

 (L. redinatum Michx.) New England and New Jersey to Wash- 

 ington (State) and northward to Alaska and Greenland. 



7. L. obscurum L. (GROUND-PINE.) Stems erect, 6' 9' 

 high, from a subterranean creeping rootstock, appearing flat 

 from the leaves of upper side being appressed ; leaves lanceolate- 

 linear, acute, entire; spikes 4 10 on each plant; bracts many- 

 rowed. (Lepidotis dendroidea Beauv.) Forms with the stems 

 more tree-like, with spreading branches and leaves 4 6-ranked, 

 are the var. dendroideum (L. dendroideum Michx.). Mountains 

 of North Carolina to Canada, and northwestward to Indiana, 

 Michigan, and Western North America. 



8. L. alpinum L. Stems elongate, creeping, with ascend- 

 ing densely clustered branches ; leaves 4-ranked, erect, imbri- 

 cated, adnate-decurrent, of two forms ; those of the lateral rows 

 lanceolate, falcate, acute, carinate, concave within ; those of the 

 intermediate rows scarcely one third smaller, lance-awl-shaped, 

 the upper and lower rows not different. (Possibly a form of 

 L. complanatum L.) Lake Superior to Rocky Mountains ; Mt. 

 Peddo, Washington (Suksdorf), and Unalaska. 



ttt Spikes erect, short-peduncled. 



9. L. sabinaefolium Willd. (GROUND-FIR.) Stems elon- 

 gate, creeping, usually underground; branches erect, short, di- 

 chotomous, clustered ; leaves 4-rowed, small, appressed, lanceo- 

 late, mucronate, entire, apparently terete ; spikes cylindric, soli- 

 tary, with cordate acuminate bracts. (Z. alpinum Michx., L. 

 armatum Desv.) New Jersey, New York, New England, and 

 northwestward. This is sometimes united with L. complanatum. 



** Fertile branches 'with minute leaves, so that the spikes ap- 

 pear long-peduncled. 



t Leaves uniform, many-ranked; stems terete. 



10. L. clavatum L. (RUNNING-PINE.) Stems extensive- 

 ly creeping; branches similar, ascending, short and leafy, the 

 fertile terminated by a slender peduncle bearing I 4 linear, 

 cylindric spikes ; leaves much-crowded, linear-awl-shaped, tipped 

 like the bracts with a fine bristle. (L. officinale Neck., L. vul- 

 gar e Vaill., L. inflexum Swz., Z,. set-pens Presl, Lepidotis inflexa 



