Lycopodiaceae

Øllgaard, Benjamin, 2012, New combinations in Neotropical Lycopodiaceae, Phytotaxa 57 (1), pp. 10-22 : 10-11

Key to the neotropical genera of Lycopodiaceae

The following key summarizes the characters that identify the nine Neotropical genera.

1 Stems isotomously branched throughout, without elongate, indeterminate main stems, but sometimes heteroblastic with creeping or subterranean shoots, from which aerial shoots arise, roots usually forming one basal tuft, sporophylls and vegetative leaves alike, or the sporophylls, if smaller, green and persisting after spore dispersal, not subpeltate and ephemeral; sporangia axillary, not attached to sporophyll, sporangium epidermis cells with sinuate, lignified side walls, spores foveolate-fossulate (subfamily Huperzioideae )................................................................. 2

- Stems anisotomously branched throughout (pseudomonopodial), the branches differentiated into elongate, indeterminate, rhizomatous, or creeping, or trailing stems, and usually determinate aerial branchlet systems; sporophylls strongly modified, ephemeral, dying after spore dispersal, unlike vegetative leaves, subpeltate or peltate, aggregated in compact, terminal strobili; sporangia borne on sporophylls or axillary, spores reticulate, rugate, or scabrate.......................................................................................................................................................................... 3

2 Plants erect or decumbent with erect or ascending shoot tips, usually with gemmiferous lateral dwarf-branchlets. Spores with equator line concave between laesurae and with truncate corners, proximal faces foveolate-fossulate. n=66, 67, 68, 132 ............................................................................................................................................. Huperzia

- Plants erect to pendulous, not gemmiferous. Spores with equator line convex between laesurae and with bluntly angular corners, proximal faces smooth, unornamented, plane. n=ca. 132, 136, 138, 170 .................... Phlegmariurus

3 Strobili erect, sessile or pedunculate, borne on aerial branchlet systems which arise in a dorso-lateral position on the creeping or subterranean, indeterminate stem; side walls of sporangium epidermis cells sinuate, lignified throughout; spores reticulate (subfamily Lycopodioideae )........................................................................................... 4

- Strobili pendulous and sessile on the branchlet systems of the tree-like aerial shoot, - or strobili erect and terminating simple (or up to twice forked) branches which arise dorsally on the creeping or looping stem; side walls of sporangium epidermis cells straight, non-lignified, except for nodular or semiannular thickenings; spores rugate (subfamily Lycopodielloideae ) ..................................................................................................................................... 7

4 Leafy branchlets isophyllous, terete ............................................................................................................................. 5

- Leafy branchlets anisophyllous, with dimorphic or trimorphic leaves, flattened and dorsiventral. ........................... 6

5. Leaf apices membranous, or terminating in a colourless hair, sporophylls subpeltate, spores reticulate on proximal faces, n=34 ...................................................................................................................................... Lycopodiums. strict.

- Leaf apices green throughout, sporophylls peltate, proximal faces of spores unornamented, n=30–32 ....................... ........................................................................................................................................................... Austrolycopodium

6 Dorsolateral leaves alternate, much larger than the partly membranous ventral leaves, spores with unornamented proximal faces. n= 34–36, 90–92................................................................................................................. Diphasium

- Leaves decussate, with large lateral leaves and narrow and smaller dorsal and ventral leaves, spores with reticulate proximal faces, n=23............................................................................................................................... Diphasiastrum

7 Strobili pendulous or nodding (erect in Palhinhaea bradei ), terminating amply branched branchlet systems which are borne on an erect, tree-like main branch; sporangia almost enclosed in cavities formed by the strobilus cortex and coalescent membranous bases of adjacent sporophylls n=104, 108, ca. 165 .............................................. Palhinhaea

- Strobili erect, terminating simple or forked, erect branches which arise dorsally on the creeping stem; sporangia enclosed and hidden by free sporophylls, or free and not concealing the sporangia ................................................... 8

8 Sporangia isovalvate; sporophylls arranged in alternating whorls of 2–5, forming 4–10 longitudinal ranks, sporangia visible between sporophylls; n=35, 68, 70...................................................................................... Pseudolycopodiella

- Sporangia anisovalvate; sporophylls arranged in alternating whorls of 5 or more, forming 10 or more longitudinal ranks; sporangia hidden by free sporophylls until dehiscence; n=78 ........................................................ Lycopodiella