Taxon Details: Megalastrum glabrius (Skottsb.) Sundue, Rouhan & R.C.Moran
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Family:
Dryopteridaceae (Pteridophyta)
Dryopteridaceae (Pteridophyta)
Scientific Name:
Megalastrum glabrius (Skottsb.) Sundue, Rouhan & R.C.Moran
Megalastrum glabrius (Skottsb.) Sundue, Rouhan & R.C.Moran
Accepted Name:
This name is currently accepted.
This name is currently accepted.
Synonyms:
Dryopteris inaequalifolia var. glabrior Skottsb.
Megalastrum inaequalifolium var. glabrior (Skottsb.) R.Rodr.
Dryopteris inaequalifolia var. glabrior Skottsb.
Megalastrum inaequalifolium var. glabrior (Skottsb.) R.Rodr.
Description:
by: M. Sundue, G. Rouhan and R.C. Moran
Lectotype: (here designated): Chile, Juan Fernández, Masafuera, i Casas-dalen [valley of the Rio Casas], 11 Feb 1917, C. Skottsberg & I. Skottsberg 466 (Lectotype: UPS, duplicate: BM)
Description: Plants terrestrial, rhizomes not seen; petioles not seen; fronds 2-pinnate-pinnatifid medially, dissection of the basal portion unknown, basal pinnae not seen; medial pinnae 45 cm long, the base sessile, overlapping the rachis; pinnules 10 cm long, sessile, overlapping the pinna costa; pinna rachises with a reddish hue, abaxially nearly glabrous, very sparsely glandular and sparsely pubescent, the hairs 0.3-0.4 mm long, 2-4 celled, hyaline, the cross walls reddish, adaxially moderately puberulent, the hairs conspicuously short, 0.1-0.3 mm long, 1-3-celled, the cross walls reddish, the apices blunt; costules with a reddish hue, abaxially very sparsely pubescent and scaly, the hairs 0.3-0.5 mm long, 2-4-celled, the scales 0.5-0.7 × 0.3-0.5 mm, ovate to lanceolate, gold-brown, translucent, entire, the cells isodiametric, adaxially moderately pubescent, the hairs 0.3-0.5 mm long, 3-4-celled; lamina tissue between the veins glabrous on both sides, abaxially glaucous, adaxially dark green; veins visible on both sides of the lamina, abaxially sparsely provided with appressed, filiform, uniseriate, reddish, scales, 0.2-0.4 mm long, adaxially glabrous; lamina margins glabrous; indusia present, 0.3-0.4 mm wide, brown, the margin ciliate, the cilia 0.2 mm long, the same color as the indusia.
Distribution: Endemic to Isla Masafuera (Alexander Selkirk Island) of the Juan Fernández Islands where it is known only from Quebrada de las Casas.
Comments: Megalastrum glabrius is known only from two fragmentary specimens, both of which were cited by Christensen (1920). The specimen at BM, collected by Skottsberg, does not have a collection number, but has the same date and locality as Skottsberg 731 at UPS. Therefore, we consider it part of that collection. It should be noted that Skottsberg 731 bis at UPS, identified as M. inaequalifolium, has a different collection date and locality. Megalastrum glabrius differs from its congeners by the absence of hairs on either side of the laminae and the lamina margins, the short-puberulent adaxial pinna rachises, and the ciliate-margined indusia. Also distinctive are the dark green color of the adaxial lamina surfaces, the glaucous abaxial surfaces, and the reddish axes.
Etymology: From the Latin glabri-, glabrous, and the comparative suffix -or/-us, more so. The specific epithet glabrius refers to the absence of hairs on either side of the laminae and the lamina margins.
by: M. Sundue, G. Rouhan and R.C. Moran
Lectotype: (here designated): Chile, Juan Fernández, Masafuera, i Casas-dalen [valley of the Rio Casas], 11 Feb 1917, C. Skottsberg & I. Skottsberg 466 (Lectotype: UPS, duplicate: BM)
Description: Plants terrestrial, rhizomes not seen; petioles not seen; fronds 2-pinnate-pinnatifid medially, dissection of the basal portion unknown, basal pinnae not seen; medial pinnae 45 cm long, the base sessile, overlapping the rachis; pinnules 10 cm long, sessile, overlapping the pinna costa; pinna rachises with a reddish hue, abaxially nearly glabrous, very sparsely glandular and sparsely pubescent, the hairs 0.3-0.4 mm long, 2-4 celled, hyaline, the cross walls reddish, adaxially moderately puberulent, the hairs conspicuously short, 0.1-0.3 mm long, 1-3-celled, the cross walls reddish, the apices blunt; costules with a reddish hue, abaxially very sparsely pubescent and scaly, the hairs 0.3-0.5 mm long, 2-4-celled, the scales 0.5-0.7 × 0.3-0.5 mm, ovate to lanceolate, gold-brown, translucent, entire, the cells isodiametric, adaxially moderately pubescent, the hairs 0.3-0.5 mm long, 3-4-celled; lamina tissue between the veins glabrous on both sides, abaxially glaucous, adaxially dark green; veins visible on both sides of the lamina, abaxially sparsely provided with appressed, filiform, uniseriate, reddish, scales, 0.2-0.4 mm long, adaxially glabrous; lamina margins glabrous; indusia present, 0.3-0.4 mm wide, brown, the margin ciliate, the cilia 0.2 mm long, the same color as the indusia.
Distribution: Endemic to Isla Masafuera (Alexander Selkirk Island) of the Juan Fernández Islands where it is known only from Quebrada de las Casas.
Comments: Megalastrum glabrius is known only from two fragmentary specimens, both of which were cited by Christensen (1920). The specimen at BM, collected by Skottsberg, does not have a collection number, but has the same date and locality as Skottsberg 731 at UPS. Therefore, we consider it part of that collection. It should be noted that Skottsberg 731 bis at UPS, identified as M. inaequalifolium, has a different collection date and locality. Megalastrum glabrius differs from its congeners by the absence of hairs on either side of the laminae and the lamina margins, the short-puberulent adaxial pinna rachises, and the ciliate-margined indusia. Also distinctive are the dark green color of the adaxial lamina surfaces, the glaucous abaxial surfaces, and the reddish axes.
Etymology: From the Latin glabri-, glabrous, and the comparative suffix -or/-us, more so. The specific epithet glabrius refers to the absence of hairs on either side of the laminae and the lamina margins.