1.  Spore-bearing leaves similar to sterile leaves, in zones on vertical stem; propagating gemmae at top;

      lacking horizontal rhizome                                                                                                                [Huperzia]  - 2

1' Spore-bearing leaves different than sterile leaves, on separate strobilus; no gemmae;

     horizontal rhizomes connect vertical stems                                                                                                           - 4


2. Leaves at bottom longer, less appressed than those at top; gemmae stalks throughout zones        - H. appressa

2' Leaves at top and bottom of same length and angle; gemmae stalks in rings only                                                  - 3


3. Leaves toothed, widest near tip; annual constrictions evident                                                        - H. lucidula

3' Leaves nearly entire, widest near base; annual constrictions not evident                                         - H. selago


4. Horizontal rhizomes surficial; vertical stems unbranched; no annual constrictions                        [Lycopodiella]  - 5

4' Horizontal rhizomes surficial or underground; vertical stems branched; annual constrictions                                - 6


5. Fertile leaves spreading; horizontal stem narrow; mostly one vertical shoot per plant                - L. inundata

5' Fertile leaves appressed; horizontal stem wide; several vertical shoots per plant                     - L. appressa

5" Fertile leaves spreading; robust; horizontal stems rootless at prominent arches                 - L. alopecuroides


6. Branches flat, with 4 ranks of leaves                                                                                  [Diphasiastrum]  - 7

6' Branches round, with 5 ranks of leaves                                                              - Diphasiastrum sitchense

6" Branches with 6 ranks of leaves, strobili sessile                                                       [(Dendro)Lycopodium]  - 9

6"' Branches with 8-10 ranks of spine-tipped leaves, strobili sessile                          [Lycopodium (Spinulum) - 11

6"" Branches with 12-20 ranks of hair-tipped leaves, strobili stalked                                         [Lycopodium] - 12


7. Plant blue-grey, conical, underside leaves overlap, horizontal stem deep        - Diphasiastrum tristachyum

7'  Plant green, underside leaves too short to overlap,    "        surficial                                                               - 8


8. Looks flat-topped, no annual constrictions on vertical branches                                           - D. digitatum

8' Looks raggedy, annual constrictions on vertical branches                                              - D. complanatum


9. Leaves on stem spreading, prickly; branch x- section round, no axial symmetry              - L. dendroideum

9' Leaves on stem appressed, branch cross section with axial symmetry                                                       - 10


10. Branches round                                                                                                                     - L. hickeyi

10' Branches flat                                                                                                                      - L. obscurum


11.  Most (10-ranked) tropophylls lack stomates on upper surface                                         - S. annotinum

11' (8-ranked) tropophylls have stomates on upper surface                                                     - S. canadense


12. Branches and tropophylls more spreading;strobili mostly multiple candlabras                      - L. clavatum

12' Branches and tropophylls more ascending; strobili single (or tightly paired)                         - L. lagopus



(some of this is borrowed from Arthur Haines)


Don Lubin ...