138 OUR NATIVE FERNS AND THEIR ALLIES. 



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

 (L. reclinatum Michx.) New England and New Jersey to 

 Washington Territory, and northward to Alaska and Greenland. 



7. L. dendroideum Michx. (GROUND-PINE.) Stems erect, 

 6' 9' high, from a subterranean creeping rootstock, densely 

 branched above, the crowded branches spreading fan-like; 

 leaves 4 6 ranked, lanceolate-linear, acute, entire ; spikes 4 10 

 on each plant; bracts many-rowed. (Lepidotis dendroidea 

 Beauv.) Forms with the stems appearing flat, from the leaves 

 of the upper side being shorter and appressed, are the var. ob- 

 scurum (L. obscurum L.) 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 Territory (Suksdorf}, and Unalaska. 



ttt Spikes erect, short-peduncled. 



9. L. sabinsefolium 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. (L. 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-shapecr, tipped 

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

 gar e Vaill., L. inflexum Swz., L. serpens Presl, Lepidotis inflexa 



