Elaphoglossum petiolatum
Description
Rhizomes short-creeping, compact, horizontal, 3–5 mm diam.; rhizome scales linear, blackish maroon to castaneous, each with tortuous hair tip, ca. 3 mm long, entire; fronds clumped, 10–39(–51) X 0.9–3.4 cm; phyllopodia distinct, but very short (2–3 mm long); stipes ca. 1⁄4 the frond length, with scales 1–2 mm long, some spreading and broader, some narrow and appressed, entire or toothed to stellate; blades narrowly elliptic, chartaceous, bases cuneate, apices acuminate; veins visible, free, simple or once-forked, ca. 1 mm apart, at 60–70° angle to costa; hydathodes absent; blade scales sparse, linear-lanceolate with hair teeth, mostly on the adaxial surfaces and on young fronds, often more abundant near the margins, occasionally with resin dots; abaxial surfaces usually with resin dots, occasionally with small linear-lanceolate scales or substellate hairs as on adaxial surface, rarely glabrous; fertile fronds slightly shorter than to far exceeding the sterile fronds but with proportionally longer stipes, ca. 2⁄3 the fertile frond length, scales on the abaxial costae, absent among sporangia absent; 2n=164 (Jam).A
A. Mickel, J. T. & Smith, A. R. 2004: The Pteridophytes of Mexico Vol. 88
Discussion
There is considerable variation in the degree of scaliness, especially on the abaxial surfaces, and the degree of resinous dotting, but the significance of this variation is not yet understood. Elaphoglossum petiolatum is widespread in tropical America, and if construed in a broad sense occurs also in the Old World tropics. In Africa it is usually called E. salicifolium (Willd. ex Kaulf.) Alston; in St. Helena, E. nervosum (Bory) Christ; in India, E. stelligerum (Wall. ex Baker) T. Moore ex Alston & Bonner; and in China, Southeast Asia, and the Pacific, E. yunnanense (Baker) C. Chr. and E. blumeanum (Fée) J. Sm. The E. petiolatum complex is characterized by having resinous dots on the abaxial blade surfaces, usually black, entire rhizome scales, and dark-tipped scales on the proximal portions of the stipes.
Mexico has several taxa in this group: E. rzedowskii in the northwest, E. potosianum in the northeast, E. pringlei in the south, and E. petiolatum throughout much of the country.
Elaphoglossum petiolatum closely resembles E. huacsaro in the resinous dots of the abaxial blade surfaces, the frequent concentration of scales along the blade margins, and the fertile fronds noticeably longer than the sterile the but E. huacsaro has more erect rhizomes and obtuse blade apices.
B
B. Mickel, J. T. & Smith, A. R. 2004: The Pteridophytes of Mexico Vol. 88
Mexico has several taxa in this group: E. rzedowskii in the northwest, E. potosianum in the northeast, E. pringlei in the south, and E. petiolatum throughout much of the country.
Elaphoglossum petiolatum closely resembles E. huacsaro in the resinous dots of the abaxial blade surfaces, the frequent concentration of scales along the blade margins, and the fertile fronds noticeably longer than the sterile the but E. huacsaro has more erect rhizomes and obtuse blade apices.
B
Specimen
Chis (Matuda 2584, F, K, MEXU, NY, US). Col (Goldsmith 41, NY). DF (Lyonnet 911, NY). Gro (Lorea 3148, NY). Gto (Rzedowski 47827, XAL). Hgo (Pringle 10837, MSC, WIS). Jal (McVaugh 14040, MICH). Méx (Rzedowski 26741, NY). Mich (Hinton 15368, NY). Mor (Lyonnet 591, NY). Nay (Rose 2210, US). Oax (Mickel 3773, NY). Pue (Marcks & Marcks 758, NY). Qro (Arguelles 1310, MEXU). Sin (Vega A. 3126, ENCB). Tlax (Sohns 654, UC). Ver (Purpus 2350, NY). Zac (Rose 2728, US).D
D. Mickel, J. T. & Smith, A. R. 2004: The Pteridophytes of Mexico Vol. 88