Lycopodium cernuum L.

  • Authority

    Proctor, George R. 1989. Ferns of Puerto Rico and the Virgin Islands. Mem. New York Bot. Gard. 53: 1-389.

  • Family

    Lycopodiaceae

  • Scientific Name

    Lycopodium cernuum L.

  • Description

    Species Description - Plants terrestrial, with horizontal-arching or assurgent main stems bearing at intervals several erect, plumose aerial branches, or sometimes the main stem itself erect, the lowermost branch decurved-spreading, elongate, and stoloniferous. Erect stems 30-100 cm long, giving rise to numerous spreading, freely branched, densely leafy lateral divisions (giving the plant a miniature treelike appearance), the ultimate branchlets (when fertile) ending in sessile cylindric-conic strobiles. Leaves of main stem spirally arranged in 16-24 ranks, often appearing nearly whorled, subulate-attenuate, mostly entire, spreading or reflexed, keeled and decurrent adaxially at base. Lateral branches to 15 cm long, bearing leaves similar to those of the main stem but slightly smaller and strongly upcurved. Strobiles often numerous, downwardly directed; sporophylls appressed-imbricate, in about 10 ranks, deltateacuminate. Sporangia subglobose with unequal valves, concealed.

  • Discussion

    Type. LINN 1257.13, from an unknown locality. Much of the Linnaean concept of this species was based on literature pertaining to Ceylon and other parts of the Old World tropics; the tropical American population was represented among the Linnaean references by Plumier, Traite & foug. Amer., t. 165, fig. A, which was based on a plant from either Hispaniola or Martinique.

    Syn. Lepidotis cemua (Linnaeus) Palisot de Beauv., Prodr. aetheogam. 108. 1805.

    Palhinhaea cemua (Linnaeus) Franco & Vasconcellos in Vasconcellos & Franco, Bol. Soc. Brot. 41: 25. 1967.

    Lycopodiella cemua (Linnaeus) Pichi-Sermolli, Webbia 23: 165. 1968.

    Two varieties occur in Puerto Rico; these have been treated as separate species, but the differences between them are small. They can be distinguished as follows

    a. Leaves glabrous or nearly so; sporophylls ca. 1.5 m m long; sporangia 0.4-0.5 m m broad 12a. var. cernuum

    a. Leaves denticulate-ciliate; sporophylls ca. 1.7 m m long; sporangia 0.6-0.8 m m broad 12b. var. curvatum.