Selaginella mollis A.Braun

Authority

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

Family

Selaginellaceae

Scientific Name

Selaginella mollis A.Braun

Description

Species Description - Stems erect from a creeping or decumbent base, ca. 2 mm diam., to 45 cm tall, not articulate, stoloniferous, light green, frequently flagelliform at apex or branches, the flagelliform tips frequently creeping some distance, sending up frondlike branches; rhizophores limited to base of erect plants, or throughout on creeping portions, filiform to stout (0.1-0.8 mm diam.); isophyllous on lower part of main stem where leaves tightly appressed and with ciliate margin, anisophyllous otherwise, leaves green above, noticeably silvery beneath, upper surfaces wrinkled and with prominently whitened midrib, often curling when dry; lateral leaves ovate-lanceolate, ca. 2 mm long, leaves barely overlapping, apex acute, base truncate on lower edge, rounded on upper edge, attached centrally or just below, upper margin long-ciliate at the base to minutely denticulate at apex, lower margin entire or minutely denticulate with a few long hairs at base; median leaves ovate, acuminate to short-aristate, biauriculate with lower auricle larger, margin long-ciliate at base, with narrow white border; axillary leaves lanceolate, exauriculate to rounded, truncate at base, margin long-ciliate; strobili narrow (1.0 mm with leaves) and 3-8 mm long; sporophylls monomorphic and of two colors (upper [median] two ranks green, lower [lateral] two ranks colorless), ascending, symmetric, with short-ciliate margins and slight keel; megasporangia in two ventral rows; megaspores white, 245-320 µm, with low anastomosing ridges; microspores yellow-orange, spinulose.

Discussion

Type. Colombia. Prov. Ocaña, Schlim 1029 “in coll. Lindeniana h. Boiss.” (G). Selaginella illecebrosa Alston, Bull. Brit. Mus. (Nat. Hist.), Bot. 1: 239, t. 5, f. A-E. 1955. Type. Guatemala. Izabal: Along lower part of stream tributary to Río Frío, Steyermark 41579 (BM!; isotype US!). The erect to secondarily creeping habit is unusual in Selaginella. The type of S. mollis from Colombia is somewhat smaller in habit than our material and its leaves less ciliate. The species is distinguished by wrinkled leaves with prominent midrib, lateral leaves long-ciliate at base, short-aristate median leaves with long-ciliate margin, long-ciliate axillary leaves and short-ciliate sporophylls. Selaginella illecebrosa Hieronymus was distinguished from S. mollis by Alston (1955) and Stolze (1983) on the basis of the erect, non-flagelliform habit and uniform stem leaves of S. illecebrosa. Specimens from Oaxaca exhibit the entire range from erect, non-flagelliform plants with uniform stem leaves to prostrate, flagelliform plants with dimorphic stem leaves, with numerous intermediate forms (erect with flagelliform branches) bridging the extremes, often on the same plants. Plants arising from the flagelliform, dimorphic branches have dimorphic stem leaves, whereas plants arising from stolons have uniform stem leaves. The leaf morphology (apices, margins, bases, etc.) of the two forms is identical.

Distribution

On rocks along streams in lower montane wet forests of Atlantic slope and Isthmus of Tehuantepec; Choapan, Ixtlán, Juchitán, Teotitlán, Tuxtepec; 100-1000 m. Mexico (Ver, Oax, Chis, Tab); Bel, Nic, CR, Pan; Col & Ven.

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