Loxogramme in Flora of China @ efloras.org

1. Loxogramme (Blume) C. Presl, Tent. Pterid. 214. 1836.

剑蕨属 jian jue shu

Authors: Zhang Xianchun & Michael G. Gilbert

Antrophyum sect. Loxogramme Blume, Fl. Javae Filic. 73. 1829.

Rhizome very shortly to long creeping, occasionally branching; roots forming a spongy mass; scales clathrate, uniformly orange-brown to blackish, entire, elongate, basifixed. Articulation between phyllopodium and frond none, or evident but not functional, or functional. Entire plant, except for roots, lacking sclerenchyma. Lamina simple, monomorphic to dimorphic, linear, narrowly elliptic, oblanceolate, or spatulate to orbicular, entire, thinly to thickly papery, margin not cartilaginous, drying revolute or involute. Lamina surface glabrous except for minute 2-celled clavate glandular hairs. Veins regularly anastomosing with many, few, or without free included veinlets; hydathodes absent. Sori exindusiate, elongate, oblique or subparallel to costa, discrete, paraphyses multicellular, hairlike. Sporangial stalk 1- or 2-celled at base; annulus with 12-16 hardened cells. Spores greenish (at time of dispersal), globose-trilete, or ellipsoid-monolete, surface finely verrucose. n = 35, 36.

About 33 species: pantropical, mainly in tropical Asia, one in Central America, one on Pacific islands, four in Africa; 12 species (one endemic) in China.

Holttum (Revis. Fl. Malaya 2: 167. 1954) suggested that the lack of articulation possibly causes the fleshy nature of the fronds, which curl up in dry weather.

Molecular data consistently indicate that Loxogramme is sister to the rest of the Polypodiaceae.

The following taxa are excluded from the present treatment, pending further research: Loxogramme elevata Ching (Bull. Fan Mem. Inst. Biol., n.s., 1: 298. 1949), described from Yunnan, L. linearis Copeland (Philipp. J. Sci., C, 11: 45. 1916), described from Taiwan, and Gymnogramma lanceolata (Linnaeus) T. Moore var. minor Baker ex Makino (Bot. Mag. (Tokyo) 10: 178. 1896).

1 Fronds dimorphic, sterile fronds suborbicular or obovate, 0.4-1 cm long and wide; fertile lamina 1-3 ?ca. 0.5 cm. 1 L. lankokiensis

+ Fronds mostly monomorphic, lamina 3-60 cm, if dimorphic or subdimorphic then lamina more than 10 cm (2)

2 (1) Fronds 3-10(-20) cm; spores globose-trilete (3)

+ Fronds 20-35 cm; spores ellipsoid-monolete (6)

3 (2) Lamina spatulate, oblanceolate, or linear-lanceolate; sori slightly sunken; rhizome scale margin slightly dentate. 2 L. grammitoides

+ Lamina lanceolate or oblanceolate; sori superficial; rhizome scale margin entire (4)

4 (3) Rhizome thick, short; scales dark brown or black; lamina 1-2.5 cm wide. 5 L. assimilis

+ Rhizome slender, long creeping; scales usually pale brown to brown; lamina 0.3-1 cm wide (5)

5 (4) Lamina 5-10(-20) ?0.5-1 cm. 3 L. chinensis

+ Lamina 3-6 ?0.3-0.4 cm. 4 L. acroscopa

6 (2) Rhizome long creeping, slender; fronds distant; stipe distinct, 2-5(-10) cm (7)

+ Rhizome short, thick, erect or creeping; fronds closely spaced or in tufts; stipe indistinct, or very short and winged (8)

7 (6) Base of stipe greenish yellow or paler. 11 L. salicifolia

+ Base of stipe glossy purplish dark brown or black. 12 L. duclouxii

8 (6) Scales thick, somewhat opaque, cells small, dense; paraphyses absent. 6 L. formosana

+ Scales thin, transparent, cells larger; paraphyses present, usually many, dense (sparse in L. cuspidata) (9)

9 (8) Scale cells ?as long as wide (10)

+ Scale cells longer than wide (11)

10 (9) Costa distinctly raised on adaxial surface; scales lanceolate, dark brown, 0.5-1.2 mm wide; sori 1-2 cm. 7 L. avenia

+ Costa not so distinctly raised on adaxial surface; scales ?triangular, grayish brown, ca. 4 mm wide; sori 3-4 cm. 8 L. involuta

11 (9) Paraphyses few, sparse; costa raised adaxially, distinct but not raised abaxially. 9 L. cuspidata

+ Paraphyses many, dense; costa flat adaxially, raised abaxially. 10 L. porcata

List of lower taxa