Cyathea alsophiloides S.Maciel & Lehnert, 2017

Maciel, Sebastião, Lehnert, Marcus, Hirai, Regina Y. & Prado, Jefferson, 2017, Three new species of the Cyathea “ Hymenophyllopsis ” clade (Cyatheaceae) from Venezuela and Brazil, Phytotaxa 329 (2), pp. 159-166 : 160-162

Cyathea alsophiloides S.Maciel & Lehnert , sp. nov. Figs. 1A–D , 3.

A new species of Cyathea “ Hymenophyllopsis ” clade, most similar to C. tepuiana Christenhusz. (2009: 41) (≡ Hymenophyllopsis steyermarkii Vareschi (1966: 89)) , both being smaller representatives of a group of generally small plants. These species are similar by absence of indument on the laminae on both surfaces. However, C. tepuiana differs in having 8–18 pinnae pairs (vs. 3–8 in C. alsophiloides ), the pinnae are congested (vs. lax), and proximally reduced (vs. pinnae not reduced), petioles 0.6–1.3 mm diam. (vs. 0.3–0.4 mm), the rhizomes robust, 4.5–15 mm diam., including roots, petioles and scales (vs. slender, 2.4–5.1 mm diam.) and indusia usually cyatheoid (vs. bivalvate).

Type:— VENEZUELA. Bolívar: Piar. Macizo del Chimantá, sección oriental del Chimantá-tepui , cabeceras del afluente derecho superior del Río Tirica (“ Caño del Grillo ”), 05º18’N, 62º03’W, 2450 m, 7–9 February 1983, J. A. Steyermark, O. Huber & V. Carreño 128825- A (holotype US barcode US 00785468!; isotype VEN, not seen) .

Plants rupicolous or rarely terrestrial. Rhizomes ascending to erect, 1.0– 1.2 mm in diam. (2.4–5.1 mm in diam., including roots, petioles and scales), with scales, surface of the rhizomes usually visible between scales, the scales lanceolate, 1.0–2.2 × 0.15–0.20 mm, concolorous, castaneous to reddish-brown, shiny, slightly contorted, bases truncate, the cells in the center of the body scales with thick walls, margins with few setiform projections towards apex, apices acute (uniseriate), 0.20–0.25 mm long, castaneous or reddish. Fronds 5.6–11.6 × 1.7–2.8 cm, caespitose, erect; petioles 0.3–0.4 mm in diam., 1.8–4.3 cm long, brown to atropurpureous, terete, basally cylindrical, slightly flattened distally, sparsely scaly at base, the scales like those on rhizomes, distally glabrous; laminae 3-pinnate, 3–8 pairs of lateral pinnae, lanceolate, 3.8–7.3 × 1.7–2.8 cm; rachises slightly rounded to mostly flattened on both sides, glabrous on both surfaces; pinnae 2-pinnate, 2–4 pairs of pinnules, alternate, ascending, 0.8–1.3 cm apart, never imbricate, flattened on both sides, apices ascending, glabrous on both surfaces; proximal pinnules pinnate, alternate, segment margins subentire, sterile pinnules 0.2–0.4 mm wide with round to subacute apices, fertile pinnules 0.4–0.7 mm wide bearing one terminal sorus. Sori 1–6 per pinna, projecting or partially immersed in the laminar tissue, laminar tissue below indusia not or only weakly constricted, sori occurring always close to the rachis on the acroscopic base of proximal pinnules, rarely on the basiscopic base; indusia bivalvate, adaxial valve ca. 0.8 mm long, margin subentire to repand, abaxial valve ca. 0.6 mm long, margins subentire to triangular-lobed; spores 32 per sporangium, trilete, yellowish.

Distribution and Ecology: — Cyathea alsophiloides is known only from Venezuela, growing on two tepuis (Chimantá-tepui and Ptarí-tepui) at high elevations (2360–2450 m), in shaded rock crevices and under ledges, on cliffs or at the entrance of small caves.

Etymology: —The specific epithet alludes to similarities of scales and frond to features typical of the genus Alsophila , i.e. narrow, almost filiform petiole scales and the skeletonized appearance of the fronds, which resemble the aphlebiae at the petiole bases found in few Neotropical species, most similar to the Brazilian Alsophila capensis (Linnaeus f. 1781: 445) Smith (1842: 666) ssp. polypodioides ( Swartz 1817: 78) Conant (1983: 369) .

Additional specimens examined (paratypes): — VENEZUELA. Bolívar: Cumbre del Ptari-tepui, al norte de la Misión de Santa Teresita de Kavanayén , 05º45’N, 61º45’W, 2360–2420 m, 23 February 1978, J. A. Steyermark et al. 115680 (US) ; Piar, Macizo del Chimantá, sección oriental del Chimantá-tepui, cabeceras del afluente derecho superior del Río Tirica (“ Caño del Grillo ”), 05º18’N, 62º03’W, 2450 m, 7–9 February 1983, J. A. Steyermark et al. 128825 ( NY), J. A. Steyermark et al. 129012 ( US) .

Notes: — Cyathea alsophiloides is recognized by having castaneous or reddish-brown rhizome scales with acute apices ending in a short, 0.20–0.25 mm, filiform, uniseriate projection and margins containing a few small setiform projections towards the apex. It has 3–8 pinna pairs that are 0.8–1.3 cm apart, pinnae and pinnules ascending and rachises and pinnae glabrous on both surfaces.

This species has proximally cylindrical and distally flattened petioles. Maybe this variation in shape of the petiole is an artifact due to the process of pressing and drying, since the leaves are very delicate.

Figures

FIGURE 1. A–D. Cyathea alsophiloides: A. Habit. B. Rhizome scale. C. Detail of the pinna adaxially.D. Detail of the indusia (Steyermark et al. 128825-A, US). E–I. Cyathea cylindrica: E. Habit. F. Rhizome scale. G. Detail of the pinna adaxially. H. Detail of the hairs catenate and clavate on the rachises. I. Detail of the indusia (Liesner 17989, US).

FIGURE 3. Distribution of Cyathea alsophiloides (stars), C. cylindrica (dot), and C. lellingeriana (triangle) in Venezuela and Brazil.