Botrychium in Flora of China @ efloras.org

1. Botrychium Swartz, J. Bot. (Schrader). 1800(2): 8, 110. 1801.

阴地蕨属 yin di jue shu

Botrypus Michaux; Japanobotrychum Masamune; Sceptridium Lyon.

Plants terrestrial or in rocky crevices, evergreen or winter-green. Rhizome short, erect, dictyostelic, glabrous or hairy, hairs long, non-septate; gemmae absent or minute, spherical, apex hairy. Roots occasionally laterally branching, yellowish to black, smooth or with corky ridges, not proliferous. Fronds 1(or 2) per stem. Common stipe thick, fleshy, glabrous or hairy. Sterile lamina ascending or perpendicular to common stipe, sessile or stalked; lamina [simple or] 1-4[or 5]-pinnate, linear, oblong, or deltoid; pinnae (reduced to segments in many species) spreading to ascending, fan-shaped to lanceolate or linear, margin entire to dentate or lacerate, apex rounded or acute; veins free, arranged like ribs of fan or pinnate. Sporophores normally 1 per frond, 1-3-pinnate, long stalked, borne at ground level to high on common stipe. Sporangia sessile to shortly stalked, almost completely exposed, large, globose, glabrous, dehiscing by 2 valves, borne in 2 rows along pinnate branches (except in very small plants). Spore surface rugate, tuberculate, baculate, sometimes joined in delicate network. Gametophytes not green, broadly ovate, unbranched. x = (44), 45, (46).

Between 50 and 60 species: nearly worldwide; 12 species in China.

Botrychium has been separated into four genera, often treated as subgenera: Botrychium, Botrypus (=B. subg. Osmundopteris (Milde) R. T. Clausen), Japanobotrychum, and Sceptridium; here, all the species are treated in a single genus.

Classification mainly follows Zou and Wagner (Amer. Fern J. 78: 122-135. 1988). Reviewer Don Farrar notes that many additional species in Botrychium subg. Botrychium have been described since the Zou and Wagner treatment and since Wagner and Wagners treatment in Flora of North America (2: 86-101. 1993), resulting in 14 diploid species (n = 45), 16 tetraploid species (n = 90), and one hexaploid species (n = 135) in North America, plus one additional diploid and one additional tetraploid in Europe for a total of 32 species worldwide. In North America, Farrar also accepts Botrychium, Botrypus, and Sceptridium as distinct genera, following the recommendations of Kato (Gard. Bull. Singapore 40: 1-14. 1987) and Hauk et al. (Molec. Phylogen. Evol. 28: 131-151. 2003).

Ching et al. (FRPS 2: 22-23. 1959) accepted Botrychium multifidum (S. G. Gmelin) Ruprecht (Beitr. Pflanzenk. Russ. Reiches 11: 40. 1859; Osmunda multifida S. G. Gmelin, Novi Comment. Acad. Sci. Imp. Petrop. 12: 517. 1768; Botrychium matricariae (Schrank) Sprengel; O. matricariae Schrank) for NE China; however, Zou and Wagner (loc. cit.: 133) noted that no Chinese specimens of B. multifidum were cited and that true B. multifidum occurs in N North America and NW Asia-NE Europe.

Japanobotrychum arisanense Masamune (J. Soc. Trop. Agric. Formosa 3: 246. 1931), the type of Japanobotrychum, was described from Taiwan.

1 Plants small, 3-15 cm; frond primordium glabrous; sterile lamina pinnate or ternate, 1- or 2-pinnate (2)

+ Plants medium-sized to large, mostly more than 10 cm; frond primordium usually hairy; sterile lamina ternately 2-4-pinnate (4)

2 (1) Pinnae fan-shaped, midribs absent. 1 B. lunaria

+ Pinnae elongate, midribs present (3)

3 (2) Pinnae rounded at apex, often overlapping; frond primordium erect. 2 B. boreale

+ Pinnae pointed at apex, usually well separated; frond primordium pendulous. 3 B. lanceolatum

4 (1) Sporophore stalk joined to sterile lamina stalk at or above base of sterile lamina (5)

+ Sporophore stalk joined to sterile lamina stalk below base of sterile lamina (7)

5 (4) Sporophore stalk joined to rachis above base of sterile lamina; frond very hairy to essentially glabrous. 4 B. lanuginosum

+ Sporophore stalk joined to base of sterile lamina; frond nearly to entirely glabrous (6)

6 (5) Ultimate segments contracted at base, deeply divided; sporangia on 2- or 3-pinnate fertile lamina; sporangial cluster deltoid. 5 B. virginianum

+ Ultimate segments not contracted, shallowly lobed; sporangia on 1-pinnate fertile lamina; sporangial cluster narrowly linear. 6 B. strictum

7 (4) Plants sparsely hairy; frond primordium with many fine hairs; sterile lamina mostly large, 10-25 cm (8)

+ Plants mostly glabrous; frond primordium glabrous or only upper part hairy; sterile lamina mostly smaller, 5-15 cm (10)

8 (7) Sporophore stalk joined to sterile lamina stalk near base of frond. 7 B. japonicum

+ Sporophore stalk joined to sterile lamina stalk 1/3-2/3 from base to sterile lamina (9)

9 (8) Sterile lamina up to 3-pinnate, papery; sporophore stalk arising 1/2-2/3 from base to sterile lamina. 8 B. daucifolium

+ Sterile lamina up to 4-pinnate, herbaceous; sporophore stalk arising 1/3-2/3 from base to sterile lamina. 9 B. formosanum

10 (7) Terminal pinnules large, differentiated from lateral pinnules, 8-15 ?5-10 mm, elongate, acute at apex, margin finely serrate; fronds mostly turning reddish in winter. 10 B. nipponicum

+ Terminal pinnules smaller, ?conform with lateral pinnules, 3-10 ?2-9 mm, rounded to truncate at apex, margin subentire to finely dentate; fronds mostly green in winter (11)

11 (10) Segments blunt, rounded, or subacute, margin entire to shallowly and coarsely crenate or dentate; sterile lamina leathery. 11 B. robustum

+ Segments mostly acute, margin shallowly to deeply denticulate; sterile lamina herbaceous. 12 B. ternatum

List of lower taxa