Ascogrammitis david-smithii (Stolze) Sundue
-
Authority
Sundue, Michael A. 2010. A monograph of
, a new genus of grammitid ferns (Polypodiaceae). Brittonia. 62 (4): 357-399. -
Family
Polypodiaceae
-
Scientific Name
-
Type
Terpsichore youngii B. León & A. R. Sm., Amer. Fern J. 93: 84-86. 2003. Type: Peru. Cuzco: Prov. Quispicanchis, montane forest facing San Lorenzo, epiphyte, pendulous, 2300-2350 m, 6 Jul 2000. B. León & K. R. Young 4487 (holotype: USM-n.v.; isotype; UC).
-
Description
Deprecated: mb_convert_encoding(): Handling HTML entities via mbstring is deprecated; use htmlspecialchars, htmlentities, or mb_encode_numericentity/mb_decode_numericentity instead in /home/emu/nybgweb/www-dev/htdocs/science-dev/wp-content/themes/nybgscience/lib/VHMonographsDetails.php on line 179
Description - Plants epiphytic, singular or forming small colonies; roots non-proliferous; rhizome 2- 3 mm wide, branch buds absent; rhizome scales 2.5-3x0.3-0.6 mm, lanceolate, the apex attenuate, clathrate, the lumina irides- cent, clear to partially occluded, the margin setose, the setae 0.1 mm long, reddish or hyaline, the colors often mixed on a single scale, the surface glabrous; fronds 18-37x3- 4 cm, hemidimorphic, arching to pendent, usually bearing the mycelia and ascomes of Acrospermum; petioles 3-11 cm x 0.7- 1 mm, with a single vascular bundle, castaneous, sparsely setose, the setae 1.0-1.5 mm long, sparsely hairy, the hairs 1 -furcate, 0.1 mm long; rachis with dark sclerenchyma visible on both sides of the blade, abaxially moder- ately setose, the setae 0.5-1 mm long, adaxially densely setose, the setae 0.5- 1(- 1.5) mm long; laminae narrowly elliptic, chartaceous, 1 -pinnate nearly throughout, the apex 1-pinnatisect, the base acute, with 1-6 pairs of reduced segments, the apex attenuate; 38-52 segment pairs; medial segments oblong, 0.9-2.5 cm x 1.6-3 mm, sessile, not or only slightly wider at the base, the base even-sided, the apex acute, the margin entire, sparsely hairy, the hairs simple, 0. 1 mm long; the abaxial lamina surface glabrous in sterile portions of the frond, moderately to densely setose in fertile portions of the frond, the setae 0.3-1 mm long, the adaxial lamina surface glabrous, or sometimes with scattered setae along the segment costae, 0.2-0.4 mm long; segment costae with castaneous sclerenchyma visible on both sides of the lamina; veins not readily visible on either side; hydathodes cretaceous; sori elongate, inframedial, 7-14 per segment confined to the distal portion of the lamina; receptacular setae present.
-
Discussion
Ascogrammitis david-smithii is distinguished by its lamina that are 1 -pinnate nearly throughout, abaxially densely setose, and segments that are parallel sided at the base and not expanded. Northern plants tend to have longer setae (up to 1.5 mm long) on the abaxial side of the rachis. Terpsichore youngii is placed here in synonymy. In the protologue of that species, León and Smith (2003) noted the similarity between A. david-smithii and T youngii. The type of T. youngii differs from A. david-smithii only by rhizome scales with elongate, curved, hyaline setae. In contrast, the rhizome scales of A. david-smithii have short, straight setae along the margin of the scale that are a mixture of hyaline and reddish in color. No other specimen has scale marginal setae that match León & K. R. Young 4487. The variation is best interpreted as variation within A. david-smithii.