Lycopodium clavatum L.

  • Authority

    Mickel, John T. & Beitel, Joseph M. 1988. Pteridophyte Flora of Oaxaca, Mexico. Mem. New York Bot. Gard. 46: 1-580.

  • Family

    Lycopodiaceae

  • Scientific Name

    Lycopodium clavatum L.

  • Description

    Species Description - Plants prostrate, long-creeping, 1-3 mm diam., sparsely rooting; lateral branches ascending to erect, 4-25 cm long; subdichotomously to pinnately forked; leaves appressed to patent, ascending or appressed, 4-8 mm long, 0.3-0.9 mm wide, spirally arranged, ending in a hair-tip 1-3 mm long; strobili cylindrical, 1-4 per peduncle, 2-9 cm long, 3-5 mm diam., on erect branches at the end of sparsely leaved peduncles, peduncles simple to 3 times sympodially forked; sporophylls deltate-ovate, margin erose, hair-tip 12 mm; sporangia reniform, valves equal.

  • Discussion

    Type. Uncertain; LINN 1257.2 was not in LINN in 1753. Linnaeus cited several references. For additional synonymy, see Øllgaard (1983). This terrestrial species is distinguished by its widely creeping stems, erect, pedunculate strobili, and hair-tipped leaves. A highly variable species or species complex, L. clavatum s.l. is in need of worldwide revision. Specimens from Oaxaca seem to exhibit two extremes (only specimens with strobili cited): 1) Strobili on long peduncles (9-16 cm), peduncle leaves entire to slightly eróse and with scarious tip, 2-4 strobili per peduncle, each on separate modified branch of peduncle; branch leaves spreading to ascending; no or indistinct annual constrictions; 600-2100 m. Examples: Mickel 905, 1006, 1515, 4158, 6766; Conrad & Conrad 32IP, Diggs 2125; Gittins 4260, 4263, 4264; Hallberg 1525; Rzedowski 815; Rzedowski & McVaugh 130; Torke et al. 497. 2) Strobili sessile or on short peduncles (to 4 cm), peduncle leaves erose with scarious tip and upper leaf margins, one strobilus per peduncle (rarely two, then paired at base of strobili, no peduncle branch); branch leaves ascending to appressed; distinct annual constrictions. Examples: Cerro Pelón, 2850 m (Mickel 1151 p.p.) and Cerro Malacate, 2700 m (Mickel 5240). Intermediate specimens occur with 1-4 strobili on the same specimens, usually with a short peduncle branch for each strobilus; peduncles 4-13 cm; branch leaves ascending to spreading or appressed. These occur mixed with the second extreme (Mickel 1151 p.p.) or at intermediate elevations of 2500 m (8200') (Mickel 4935 and Pringle 1307). Studies in Japan with L. clavatum (Takamiya & Tanaka, 1982; Tanaka & Takamiya, 1981) showed sympatric populations made up of three cytotypes (2x, 3x, 4x; n = 34) which correlated with the number of strobili, length of peduncle, length of peduncle branches and leaf orientation. They observed mitotic chromosomes and presented no data concerning spore abortion or size. The Oaxaca material shows no correlation of larger spore size (27-32 µm range) with either extreme and no evidence of spore abortion (as expected in triploid hybrids). These extremes could be two diploid species with the intermediate diploid hybrids, such as found in the L. complanatum group, with perfect meiotic pairing and no spore abortion (Hersey & Britton, 1981; F. Wagner, 1980) or phenotypic modification by environmental factors. Interestingly, the extreme Mexican specimens resemble specimens from high elevation in Costa Rica (e.g., Taylor 4351, NY), which are themselves intermediate in morphology between typical L. clavatum and L. contiguum Klotzsch (e.g., Mickel 3250, NY), a paramo species with sessile or extremely short-peduncled strobili, tightly incurved rigid leaves, distinct annual constrictions, and sporophylls with long, scarious tips and margins. These intermediate Costa Rican specimens (L. clavatum x contiguum) also do not exhibit spore abortion. The Oaxacan extreme and intermediate specimens from high elevation may represent relict populations of this hybrid.

  • Distribution

    Terrestrial on banks and exposed slopes, montane rain forest or pine-oak forests; Centro, Cuicatlán, Ixtlán, Mixe, Pochutla, Teotitlán, Villa Alta; 650-3200 m. Mexico (Mich, Gro, Hgo, Ver, Pue, Oax, Chis); north temperate regions of North America; Guat to Pan; WI; Col & Ven, to Bol & Braz; n Europe, temperate and tropical regions of Asia and Pacific Basin.

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