'ekaha, hoe a Maui ("Maui's paddle"), Hart's tongue ferns
Latin elaphos, deer, stag, hart, +glossa, tongue, in reference to the shape of the frond.
Plants small to medium-sized, terrestrial or epiphytic. Rhizomes short- or long-creeping, bearing scales of various types. Fronds clustered or distant. Stipes winged or not. Blades dimorphic. Sterile blades simple, elliptic to oblanceolate, entire, coriaceous or less often chartaceous to membranous. Fertile blades usually differing from sterile blades in size and shape, abaxial surfaces covered with sporangia. Veins free, parallel, or free and uniting at margins to form a continuous marginal commissural vein, or veins reticulate.
A pan tropical to south-temperate, uncommonly north-temperate genus of about 600 species, with the greatest diversity in tropical America. Important features for differentiating species include character and size of scales; venation pattern; character of rhizomes; presence or absence of winged stipes; and size, shape, and texture of fronds.
Represented in Hawai 'i by eight endemic and one indigenous species and two known interspecific hybrids.
Four of the Hawaiian species (E. alatum, E. crassicaule, E. fauriei, E. parvisquameum) belong to a monophyletic endemic species swarm (the Alatum group) characterized by mostly to completely winged stipes and parallel and forking veins that unite to form a continuous marginal commissural vein. The character of the scales is important in differentiating species of the Alatum group.
KEY TO THE SPECIES OF ELAPHOGLOSSUM IN HAWAI'I
I. Fronds heavily covered with scales; fronds with a nodding growth form; all major islands except Lana 'i ............................. 6. E. paleaceum
I. Fronds glabrous or with scattered scales; fronds erect (2).
2(1 ). Veins reticulate; laminae very leathery; all major islands ....... 4. E. crassifolium
2. Veins free, or free except joining at margins to form marginal commissural veins; frond texture leathery to membranous (3).
3(2). Margins lacking commissural veins; stipes without wings (4).
3. Margins with continuous commissural veins; stipes with wings extending nearly to base (Alatum group) (6).
4(3). Rhizomes more than 1.5 cm diam. (with scales), obscured by thick masses of scales; scales 1-3 cm long; all major islands . . . . . . . . . . . . . . . . I. E. aemulum
4. Rhizomes diam. 0.5 cm or less (with scales), not obscured or covered with short scales, or scales present at rhizome tips and soon deciduous; scales 2-3 mm long (5).
5(4). Sterile blades chartaceous, delicate, translucent; veins prominent; stipes and blade surfaces with many small, globular, pellucid, amber-colored glands, without scales; rhizomes less than 2 mm diam., long-creeping; all major islands except Lana'i .................................. 8. E. pellucidum
5. Sterile blades coriaceous; veins obscure; stipes and blade lacking glands, often minutely scaly; rhizomes 3-5 mm diam., tips scaly, short-creeping; all major islands except Lana'i ............................. 9. E. wawrae
6(3). Rhizomes densely covered with soft, long, narrowly lanceolate, twisted scales, scales 10-25 mm long; O'ahu ........................ 2. E. alatum
6. Rhizomes with smaller scales, scales stiff and shiny, straight or curled over at tips, 1-7 mm long; O'ahu and other islands (7).
7(6). Rhizome scales dark brown to black, stiff, straight, 3-7 mm long; O'ahu, Moloka'i .............................................. 5. E.fauriei
7. Rhizome scales light to dark brown to black, curled over at tip, 1-5 mm long; Kaua'i, Moloka'i, Lana'i, Maui, Hawai'i (8).
8(7). Blades elliptic to oblanceolate, 15-45 x 4-7 cm; rhizomes covered with tiny, brittle, light to dark brown to black, triangular to lanceolate scales 1-2 x 1 mm; phyllopodia prominent, more than 1.5 cm long; Moloka'i, Uina'i, Maui, Hawai 'i ................................... 7. E. parvisquameum
8. Blades broadly oblanceolate, 35-60 x 5-8 cm; rhizomes densely covered with small, firm, dark brown to black, lanceolate-acuminate scales (2-)3- 5 x 1-2 mm; phyllopodia less than 1 em long, making rhizomes appear thicker; Kaua 'i ....................................... 3. E. crassicaule
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ADBC 1304924
and ADBC1115116).
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