Ctenitis megalastriformis R.S. Viveros & Salino (2017: 317)

Viveros, Raquel Stauffer, Rouhan, Germinal & Salino, Alexandre, 2018, A taxonomic monograph of the fern genus Ctenitis (Dryopteridaceae) in South America, Phytotaxa 385 (1), pp. 448-450 : 448-450

17. Ctenitis megalastriformis R.S. Viveros & Salino (2017: 317) . Figs. 05E, 10D, 23 B. Type: — PERU. Madre de Dios: Manu. Close to the village of Diamante, southern side of río Alto Madre de Dios. Primary rainforest on flat and clayey upland terrain, Tuomisto 13393 (holotype UC 1787981!, UC 1787982!, UC 1787983!, isotype TUR 587076 [image!], TUR 587077 [image!], TUR 587078 [image!]).

Stems not seen; leaves 140 cm long; petioles 44.5 cm × 4.9 mm, with 5 vascular bundles at base, brownish, scales 7.9–10.5 × 0.3–0.4 mm, castaneous, clathrate, tangled on petiole base, becoming patent or ascending towards distal portion, flattish, flaccid, linear with truncate base and filiform apex, entire, without fimbriae, catenate trichomes absent abaxially, glandular trichomes absent; laminae 95.5 × 50.5 cm, wider than 1/2 of length, 2-pinnate-pinnatifid basally, 1-pinnate-pinnatisect medially, 1-pinnate-pinnatifid apically, ovate, apex confluent; rachises tan or stramineous, scales like those on distal portion of petioles, catenate trichomes absent abaxially, sparse glandular trichomes; pinnae 14 pairs, the basal and medial ones stalked to 18.0 mm long, the apical ones sessile, basal pinnae basiscopically and acroscopically somewhat equally developed, the medial 22 × 2.5 cm, lanceolate, incised more than 3/4 of the distance between the segment apex and costa, basal segments shorter than the next, apex attenuate; adaxial pinnae axes with sparse scales on costa, 1.5–1.7 × 0.1–0.2 mm, castaneous, lanceolate, catenate trichomes dense on costa and costule, bacilliform trichomes absent; adaxial laminar surface between veins glabrous; abaxial pinnae axes with sparse scales on costa and costule, 1.2–3.1 × 0.3–0.4 mm, castaneous, clathrate, ascending, flattish, flaccid, lanceolate with rounded base and filiform apex, entire or slightly denticulate, with or without some short fimbriae at base, proscales absent, catenate trichomes absent, bacilliform trichomes sparse on costa, costule and veins, glandular trichomes sparse on costa, filiform trichomes absent; abaxial laminar surface between veins glabrous or with rare bacilliform trichomes; segments 20–26 pairs, 8.3–11.6 mm wide, patent or subfalcate, serrate, apex acute, margin with catenate trichomes, the distance from each other is narrower than segments width; veins 1–3-forked, 12–13 pairs per segment (before forking), the basal ones from adjacent segments end before the margin, towards above the sinus; sori inframedial, indusia absent; spores with coarse folds.

Habitat and distribution:— Terrestrial in rainforest, about 150 m. Known only from Peru ( Viveros & Salino 2017; Fig. 23B ; Tab. 01) .

Notes:— Ctenitis megalastriformis can be recognized by lamina 2-pinnate-pinnatifid basally (with distinct free, but adnate pinnules at base of basal pinnae, but along medial and apical portion of the basal pinnae it “becomes” pinnatisect to pinnatifid; Fig. 05E). However, it is 1-pinnate-pinnatisect medially and 1-pinnate-pinnatifid apically. The segments are serrate, the veins 1–3-forked, the basal ones, from adjacent segments end before margin, changing its direction brusquely towards above the sinus, the sori are inframedial and without indusia. The indument are scarse, either by scales or by trichomes. The scales are very sparse, castaneous and lanceolate, on abaxial pinnae axes there are some bacilliform trichomes on costa, costule and veins, some glandular trichomes on costa abaxially and the abaxial laminar surface between vein is glabrous or with rare bacilliform trichomes. Such morphological characters of C. megalastriformis are illustrated in Viveros & Salino (2017). The spores of this species ( Fig. 10D ) are much smaller than the other species treated here.

54 • Phytotaxa 335 (1) © 2018 Magnolia Press

VIVEROS ET AL.

Figures

FIGURE 10. Spores of Ctenitis from South America. A: C. glandulosa (Salino 13626, BHCB, from Viveros & Salino 2015). B: C. grisebachii (Underwood 445, NY). C: C. laetevirens (Schimitt 561, BHCB). D: C. megalastriformis (Tuomisto 13393, UC). E: C. microchlaena (Mickel 2626, NY). F: C. nervata (Almeida 1682, BHCB). G: C. nigrovenia (Salino 15212, BHCB). H: C. paranaensis (Kozera 356, BHCB, from Viveros & Salino 2015). I: C. refulgens var. refulgens (Salino 15242, BHCB). J: C. refulgens var. peruviana (Schunke 5941, NY). K: C. submarginalis var. submarginalis (Verdi 1843, BHCB). L: C. submarginalis var. tenuifolia (Pietrobom 5015, BHCB). Scales bars = 10 µm.

FIGURE 23. Distribution of four species of Ctenitis in South America. A: C. laetevirens. B: C. megalastriformis. C: C. microchlaena. D: C. nervata.