AcroRUMOHRA (H. Itô) H. Itô in Nakai & Honda, Nov. Fl. Jap. 4: 101. 1939. [Draft]

假复叶耳蕨属  jia fu ye er jue shu

Rumohra sect. Acrorumohra H. Itô, J. Jap. Bot. 11: 583. 1935.

Plants terrestrial, mid-sized. Rhizome erect, short, clothed with scales; scales linear to linear-lanceolate or ovate, margin entire. Fronds tufted; stipe base scales like those of rhizome, becoming glabrous above; lamina broadly lanceolate, ovate, or pentagonal, (2- or)3- or 4-pinnate; ultimate pinnules or segments obliquely ovate or elliptic, without aristate teeth along margin or at apices, basal acroscopic segment often slightly auriculate, ± adnate to axes; texture herbaceous or papery; subglabrous on both surfaces; veins free, veinlets simple or 1(or 2)-times forked, ending short of margin, tip not enlarged; arrangements of pinnules, segments, and veins anadromous throughout. Sori round, terminal on acroscopic veinlet branches, (occasionally subdorsal on veinlets); indusia reniform and entire, or absent; sporangia numerous, without glands on pedicels, annulus of 14–17 thickened cells. Spores ellipsoid; surface lophate. x=41.

About four or five species in tropical and subtropical areas of S and SE Asia, extending to the Pacific islands; four species in China (two endemic).

Although most authors treat Acrorumohra species in the genus Dryopteris Adanson, here they are recognized as a separate genus intermediate between the genera Arachniodes Blume and Dryopteris Adanson.

1a.     Rachis straight; pinna stalks ascending toward frond apex.

2a.    Lamina 3-pinnate; sori exindusiate ...............................................................  1. A. hasseltii

2b.    Lamina 2-pinnate; sori indusiate .......................................................................  2. A. yoroi

1b.     Rachis zigzag, pinna stalks deflexed toward base.

3a.    Rachis strongly zigzag; basiscopic angles between pinna stalks and stipe or rachis up to 30°  3. A. diffracta

3b.    Rachis slightly zigzag; basiscopic angles between pinna stalks and stipe or rachis up to 70°  4. A. subreflexipinna

 

1. Acrorumohra hasseltii (Blume) Ching, Acta Phytotax. Sin. 9: 385. 1964.

草质假复叶耳蕨  cao zhi jia fu ye er jue

Polypodium hasseltii Blume, Fl. Javae Fil. 195. 1851[??1829]; Arachniodes hasseltii (Blume) Ching; Byrsopteris hasseltii (Blume) C. V. Morton; Dryopteris adiantoides T. Suzuki; D. hasseltii (Blume) C. Christensen; D. obovata (Baker) C. Christensen; D. psilosora Tagawa; Nephrodium obovatum Baker; Phegopteris hasseltii (Blume) Mettenius; Polystichopsis hasseltii (Blume) Holttum; Rumohra hasseltii (Blume) Ching.

Rhizome apex densely covered with castaneous scales. Fronds 0.7–1.1 m; stipe stramineous, rather paler when dried, 30–60 cm, 2–4 mm in diam., base and lower parts densely scaly; scales dull brown, lanceolate, ca. 15 × 1.5 mm, upward glabrescent or with scattered smaller scales; lamina 3-pinnate, deltoid or ovate-oblong, 45–60 × 25–35 cm; pinnae 10–16 pairs, alternate, stalked, obliquely spreading, lowest pinnae ovate-lanceolate, 18–25 × ca. 7 cm, base rounded-cuneate, apex acuminate, 2-pinnate; penultimate pinnules ca. 15 pairs, shortly stalked, lanceolate or oblong; basal basiscopic ones larger, broadly lanceolate, 7–9 × 2.5–4.5 cm, 1-pinnate; ultimate pinnules 9 or 10 pairs, shortly stalked or sessile distally, ovate-oblong, ca. 1.3 × 0.7 cm, slightly auriculate at base above, cuneate below, apex obtuse, margin shallowly pinnatifid with lobes blunt at apex, basal ones often with acroscopic lobe free and apex with 2 or 3 obtuse teeth; upper pinnae gradually reduced to pinnatifid lamina apex; texture herbaceous, yellowish green when dried; costae (axes of ultimate pinnules) sometimes with minute brown lanceolate scales abaxially. Sori terminal on veinlets, 1–5 pairs per ultimate segment, medially between midvein and margin, and exindusiate.

Understories of broad-leaved forests, especially in valleys; 400–1800 m. Hainan, Taiwan, Yunnan [NE India, Indonesia, Japan, Malaysia, Nepal, New Guinea, Philippines, Singapore, Sri Lanka, Thailand, Vietnam; Pacific islands].

2. Acrorumohra yoroi (Serizawa) W. C. Shieh, J. Sci. Engin. (Nation. Chung-Hsing Univ.) 12: 301. 1975.

玉山假复叶耳蕨  yu shan jia fu ye er jue

Dryopteris yoroii Serizawa, J. Jap. Bot. 46: 20. 1971.

Rhizome [??]. Fronds 27–34 cm; stipes 14–16 cm and ca. 2 mm in diam., base densely scaly; scales reddish or castaneous, lanceolate, up to 10 mm, apex attenuate to a threadlike tip; scales above stipe base dimorphic: (1) narrower ones bicolorous with center castaneous and edge pale brown, lanceolate, 4.5–6 × 1–1.5 mm, firmly membranous, base rounded, apex acuminate, (2) broader ones light brown, ovate or ovate-lanceolate, 5–7 × 2.5–4 mm, base rounded, apex acute; lamina 2-pinnate, narrowly ovate, 13–18 × 7–11 cm, base rounded-cuneate, apex attenuate or acuminate; pinnae ca. 8 pairs, with stalks up to 5 mm, distant, deltoid-lanceolate, lowest pinnae 5–7 cm, 1-pinnate; ultimate pinnules shortly stalked, deltoid-ovate, 1.5–2 × 0.9–1.3 cm, base truncate, nearly equally sided, apex obtuse, margin shallowly pinnatifid, lobes obtuse at apex; upper pinnae gradually reduced; pinnules elliptic, 0.7–1.1 cm, base acroscopically broadly cuneate and often auriculate, basiscopically cuneate, margin pinnatifid, apex obtuse or rounded; texture firmly herbaceous, yellowish green when dried; rachis and costae with scattered scales abaxially, elsewhere with sparse multicellular hairs. Sori subdorsal on veinlets, closer to midvein than to margin; indusium[??]

* [Habitat??; elevation??]. Taiwan (Yu Shan).

3. Acrorumohra diffracta (Baker) H. Itô in Nakai & Honda, Nov. Fl. Jap. 4: 101. 1939.

弯柄假复叶耳蕨  wan bing jia fu ye er jue

Nephrodium diffractum Baker, Bull. Misc. Inform. Kew. 1898: 230. 1898; Arachniodes diffracta (Baker) Ching; Aspidium diffractum (Baker) H. Christ; Dryopteris diffracta (Baker) C. Christensen; D. reflexipinna Hayata; Polystichum diffractum (Baker) Masamune; Rumohra diffracta (Baker) Ching.

Rhizome with dense dark brown scales. Fronds 50–100 cm; stipe stramineous or dark brown basally, 20–55 cm and 2–4 mm in diam., base with brown linear-lanceolate and acuminate scales, glabrescent upward; lamina 4-pinnate, broadly ovate, 25–45 × 20–32 cm, base deeply cordate, apex acuminate; pinnae 6–8 pairs, alternate, stalked, stalks deflexed and forming an angle of ca. 30° with extremely zigzag rachis downward from point of attachment; lowest pinna deltoid, ca. 18 × 15 cm, base asymmetric, apex acute or acuminate, 3-pinnate; pinnules 7–9 pairs, stalked, spreading or deflexed, oblong-lanceolate, 9–11 × 4–5 cm, base unequal, apex caudate-acuminate, 2-pinnate; penultimate pinnules 7 or 8 pairs, stalked, broadly ovate, 1.8–2.5 × 1.5–2.5 cm, base rounded, apex obtuse, 1-pinnate; ultimate pinnules 3 or 4 pairs, shortly stalked, broadly ovate, 1.2–1.8 × 0.8–1.5 cm, base cuneate, apex obtuse to acute, margin pinnatifid, proximal lobes often nearly free, broadly ovate, margin with 3–5 obtuse teeth; upper pinnae gradually reduced to a pinnatifid apex; texture herbaceous, green when dried; costae, costules, and veins occasionally with red-brown lanceolate minute scales or appressed articulate hairs abaxially. Sori small, terminal on veinlets, 1–3 pairs on each ultimate segment; indusia brown, papery, entire, fugacious.

On wet slopes under broad-leaved forests or bamboos; 700–2500 m. Guangxi, Guizhou, Hainan, Taiwan, Xizang, Yunnan [SE India, Myanmar, Thailand, Vietnam].

The occurrence of Acrorumohra diffracta in Guizhou is questionable since no specimen has been collected there since the one gathered by Cavalerie.

4. Acrorumohra subreflexipinna (M. Ogata) H. Itô in Nakai & Honda, Nov. Fl. Jap. 4: 102. 1939.

微弯假复叶耳蕨  wei wan jia fu ye er jue

Dryopteris subreflexipinna M. Ogata, J. Jap. Bot. 11: 30. 1935; Arachniodes subreflexipinna (M. Ogata) Ching; Rumohra subreflexipinna (M. Ogata) H. Itô.

Rhizome apex densely covered with brown lanceolate scales. Frond 65–85 cm; stipe dark brown when young and brownish with age, 40–45 cm and 2–4 mm in diam., base densely scaly, upward and throughout rachis with sparse scales; lamina 4-pinnate, ovate-oblong, 25–40 × 22–37 cm, base rounded, apex acute; pinnae 7 or 8 pairs, alternate, approximate, stalked, stalks slightly deflexed and forming an angle of ca. 70° with somewhat zigzag rachis downward from point of attachment; lowest pinna narrowly deltoid, ca. 25 × 18 cm, base broadly cuneate, apex acuminate, 3-pinnate; pinnules ca. 14 pairs, stalked, spreading or bent proximally, basal basiscopic one elongated, deltoid-lanceolate, ca. 14 × 4–5 cm, base cuneate, apex acuminate, 2-pinnate; penultimate pinnules ca. 10 pairs, stalked, basal basiscopic one larger, narrowly deltoid, 1.8–2 × 0.8–1.2 cm, base rounded-cuneate, apex obtuse, 1-pinnate; ultimate pinnules 3 or 4 pairs, basal 1(or 2) pairs free, ovate, ca. 1 × 0.5 cm, base obliquely truncate, apex rounded; upper pinnae gradually reduced; texture herbaceous, green when dried; costae with brown lanceolate minute scales abaxially. Sori terminal on veinlets, 1–3 pairs on each ultimate segment; indusium brown, papery, entire, fugacious.

* [Habitat??; elevation??]. Taiwan (Hualian).