Kev To The Lvcopodiums. 



I. — Sporangia in the axils of ordinary leaves 



Leaves flat. Lowland species . . L. hiciduhttn 



Leaves curved upward. Mountain species L. sclago 

 IL — .Sporangia in cone-like spikes 



Sterile stems prostrate ; fertile, erect, unbranched 



Prostrate stems usually branched L. alopecuroidis 

 Prostrate stems short, seldom branched 



Rooting throughout L. Caroliniamim 



Rooting at base and tip only . L. intindattuii 

 Fertile and sterile stems erect; rootstock creeping- 

 Cones closely sessile 



A\'eraging an inch or more long L. obsciiriim 

 Averaging less than an inch long 



L. annotiniim 

 Averaging less than half an inch long 



L. cernuiiin 

 Cones apparently stalked 



Branches about four-sided . L. alpiiium 



liranches round 



Leaves bristle-tipped, i inch long 



L. chx'i'atuin 

 Leaves not bristle-tipped, shorter 



L. SitcJtense 

 Branches flattened 



Cones two to four, peduncle long, stout 



L. coiiiplaiiatiim 

 Cones one to three, peduncle short, slender 

 L. sabincefolium 



