Polystichum sect. Hypopeltis in Flora of China @ efloras.org

14. Polystichum sect. Hypopeltis (Michaux) T. Moore, Index Fil. 84. 1857.

后生耳蕨组 hou sheng er jue zu

Hypopeltis Michaux, Fl. Bor.-Amer. 2: 266. 1803; Polystichum sect. Aculeata Christ; P. sect. Metapolystichum Tagawa; P. sect. Scleropolystichum Daigobo.

Plants medium-sized to large, evergreen or summer-green, rarely small. Lamina papery or thinly papery, rarely thickly papery, bipinnate, not finely dissected. Rachis without proliferous bulbils. Pinnules stalked or sessile. Microscales narrow-type.

About 70 species: worldwide; 42 species (25 endemic) in China.

It is a dilemma in which section to place Polystichum aculeatum, the type of P. sect. Hypopeltis. Polystichum aculeatum evidently originated as a hybrid between P. lonchitis and P. setiferum (Forsskål) Moore ex Woynar. The chloroplast data place it in P. sect. Metapolystichum, but its hard spinules on the frond margins and its frond texture resemble those of P. lonchitis, which, as the type of Polystichum, belongs to P. sect. Polystichum. FRPS (5(2): 52. 2001) placed P. aculeatum in P. sect. Scleropolystichum (= P. sect. Xiphopolystichum) based on its hard spinules on the frond margins and its hard frond texture. Here, we place it in P. sect. Metapolystichum based on its overall morphology and its maternal origin. Therefore, the correct name for this section becomes P. sect. Hypopeltis, which is earlier (1857) than P. sect. Metapolystichum (1940).

The currently defined Polystichum sect. Hypopeltis is possibly not monophyletic. The delimitation between P. sect. Hypopeltis and P. sect. Sorolepidium is not clear because there are polyploids in both sections that are intersectional hybrids. Some alpine species may need to be moved to P. sect. Sorolepidium.

The Chinese species of Polystichum sect. Hypopeltis can be divided into six series based on morphology.

1 Plants evergreen; pinnae leathery, stiff, with hard spinules on margin (1. P. ser. Hypopeltis). 79 P. aculeatum

+ Plants evergreen or summer-green; pinnae thinly papery, papery or thickly papery, not stiff, with soft spinules or without spinules on margin (2)

2 (1) Microscales shorter than 0.6 mm (short-type) (3)

+ Microscales longer than 1 mm (long-type) (19)

3 (2) Veins clavate and unusually swollen at ends (hydathodes) (3. P. ser. Exauricula). 98 P. punctiferum

+ Veins linear and not unusually swollen at ends (4)

4 (3) Stipe with only linear and linear-lanceolate scales (5. P. ser. Linearia) (5)

+ Stipe with ovate, ovate-lanceolate, or broadly lanceolate scales (6. P. ser. Makinoiana) (8)

5 (4) Lower pinnae contracted toward lamina base; pinnules ca. 0.5 cm, nearly leathery. 106 P. tangmaiense

+ Lower pinnae not or slightly contracted toward lamina base; pinnules longer than 0.6 cm, papery (6)

6 (5) Lamina often 20(10-35) cm wide; pinnules with obvious aristate spinules on margin; rachis scales dark brown, linear and straight; apex of lamina often sterile; indusia lacerate. 107 P. discretum

+ Lamina often 10(<20) cm wide; pinnules with or without obvious aristate spinules on margin; rachis scales brown, linear and tortuous (7)

7 (6) Lamina oblong-lanceolate, ratio of length to width ca. 4; rachis scales sparse; pinnae strongly curved upward, caudate; lower basal pinnules of lower pinnae not contracted; sori in 1 or 1.5 rows per pinnule; indusia entire or almost entire. 108 P. oligocarpum

+ Lamina deltoid or broadly lanceolate, ratio of length to width ca. 2.3(-3.5); rachis scales dense; pinnae not or slightly curved upward, acute or acuminate; lower basal pinnules of lower pinnae contracted; sori in 2 rows per pinnule; indusia lacerate. 109 P. weimingii

8 (4) Rachis scales bicolorous: brown and blackish brown (9)

+ Rachis scales concolorous (13)

9 (8) Except rachis base, rachis without ovate-lanceolate scales; pinnules falcate-deltoid (10)

+ Rachis with ovate-lanceolate scales (11)

10 (9) Pinnules with open spinules; indusia shallowly toothed. 110 P. makinoi

+ Pinnules with forward-pointing spinules; indusia entire. 111 P. otomasui

11 (9) Lamina deltoid-lanceolate; pinnule falcate-deltoid; microscales lanceolate (broad-type) 112 P. parvifoliolatum

+ Lamina oblong-lanceolate or elliptic; pinnule oblong or deltoid-ovate; microscales linear (narrow-type) (12)

12 (11) Lamina oblong-lanceolate, ratio of length to width ca. 3:1; pinnae acuminate or acute, basalmost 1 or 2 pairs often sterile; pinnules oblong, acroscopic margins nearly not toothed but with long or short spinules; microscales dense abaxially. 113 P. piceopaleaceum

+ Lamina elliptic, ratio of length to width ca. 2.5:1; pinnae often caudate, basalmost 1 or 2 pairs often fertile; pinnules deltoid-ovate, acroscopic margins shallowly toothed or dissected halfway to midrib and with long spinules; microscales sparse abaxially 114 P. yunnanense

13 (8) Sori marginal (14)

+ Sori medial or close to midrib (16)

14 (13) Lamina deltoid-lanceolate; rachis scales linear and subulate; pinnules falcate-deltoid, acuminate at apex, auricles deltoid; indusia erose. 115 P. acutipinnulum

+ Lamina deltoid-ovate; rachis scales lanceolate and linear; pinnules oblong or oblong-ovate, obtuse at apex, auricles rounded (15)

15 (14) Whole lamina fertile; acroscopic margins of pinnules without or rarely with few short spinules; indusia entire. 116 P. pseudomakinoi

+ Only upper part of lamina fertile; acroscopic margins of pinnules with few short spinules; indusia irregularly lacerate. 117 P. shimurae

16 (13) Nearly whole rachis with ovate-lanceolate scales; pinnules long spinulose on margin (17)

+ Rachis without or only lower part with ovate-lanceolate scales; pinnules shortly spinulose on margin (18)

17 (16) Microscales long filiform, obviously present on adaxial surface of pinnules; acroscopic margins of pinnules shallowly toothed or incised, basal acroscopic pinnules prolonged and pinnatifid; indusia entire. 118 P. huae

+ Microscales shortly filiform, few or absent on adaxial surface of pinnules; acroscopic margins of subentire, basal acroscopic pinnules prolonged but not pinnatifid; indusia erose. 119 P. longiaristatum

18 (16) Plants up to 80 cm tall; rachis scales not regularly reflexed. 110 P. makinoi

+ Plants up to 100 cm tall; rachis scales regularly reflexed. 120 P. subulatum

19 (2) Plants summer-green, lamina thinly papery, yellowish green, narrowly lanceolate or narrowly elliptic-lanceolate, rarely broadly deltoid-lanceolate (P. bakerianum, P. rufopaleaceum, P. sinense); stipe stramineous or brown when dry; pinnules or free lobes fewer than 6(-10) pairs (up to 15 pairs in P. bakerianum, P. rufopaleaceum, and P. sinense), sessile (2. P. ser. Sinensia) (20)

+ Plants evergreen or rarely summer-green (P. braunii); lamina green, broadly lanceolate, broadly deltoid-lanceolate, or broadly elliptic-lanceolate; stipe greenish when dry; pinnules 10-30 pairs, stalked (34)

20 (19) Pinnae or lobes obviously aristate-spinulose (21)

+ Pinnae or lobes only crenate to serrulate (25)

21 (20) Stipe brown or dark brown (22)

+ Stipe stramineous (23)

22 (21) Stipe brown; lamina oblanceolate. 83 P. bomiense

+ Stipe dark brown; lamina lanceolate or elliptic. 84 P. tibeticum

23 (21) Stipe and rachis scales bicolorous: brown with blackish brown centers. 80 P. pseudocastaneum

+ Stipe and rachis with brown scales only (24)

24 (23) Middle pinnae 1.5-2 cm, not falcate. 81 P. prescottianum

+ Middle pinnae 3-3.5 cm, slightly falcate. 82 P. yadongense

25 (20) Stipe scales bicolorous: brown and blackish brown (26)

+ Stipe scales concolorous: brown or dark brown (29)

26 (25) Stipe brown at lower part; pinnae obtuse or acute at apex. 91 P. saxicola

+ Stipe stramineous (27)

27 (26) Lamina bipinnate; large bicolorous scales ovate. 92 P. kangdingense

+ Lamina bipinnatipartite; large bicolorous scales lanceolate (28)

28 (27) Pinnae 26-32 pairs; lobes narrowly ovate or lanceolate. 93 P. frigidicola

+ Pinnae 12-24 pairs; lobes obliquely oblong or rhombic-ovate. 94 P. submite

29 (25) Stipe brown at least at lower part (30)

+ Stipe stramineous, sometimes brownish at base (31)

30 (29) Pinnae deltoid-lanceolate, ratio of length to width ca. 2; lobes fewer than 4 pairs. 85 P. qamdoense

+ Pinnae lanceolate, ratio of length to width 3 or larger; lobes 8-12 pairs. 86 P. gongboense

31 (29) Lamina wider than 18 cm at middle; middle pinnae with 12 or more pairs of pinnules; stipe scales reddish brown or brown (32)

+ Lamina narrower than 14 cm at middle; middle pinnae with fewer than 10 pairs of pinnules or lobes; stipe scales yellowish brown or light brown (33)

32 (31) Stipe base with broadly lanceolate scales; pinnules with open teeth; sori indusiate. 87 P. bakerianum

+ Stipe base with ovate scales; pinnules with forward-pointing teeth; sori exindusiate. 88 P. rufopaleaceum

33 (31) Stipe with ovate scales; lamina papery; rachis with broadly lanceolate or narrowly ovate scales. 89 P. sinense

+ Stipe scales lanceolate; lamina thinly papery; rachis with linear or filiform scales. 90 P. mollissimum

34 (19) Rachis scales broadly ovate to ovate-lanceolate; pinnules of upper pinnae exauriculate (3. P. ser. Exauricula) (35)

+ Rachis scales various forms; pinnules of upper pinnae obviously auriculate (4. P. ser. Brauniana) (37)

35 (34) Large rachis scales relatively sparse, blackish brown to dark brown; stipe scales relatively sparse; lamina sterile at apex; sori indusiate. 97 P. pianmaense

+ Large rachis scales dense, light brown to brown; stipe scales dense; lamina fertile at apex; sori exindusiate (36)

36 (35) Stipe scales brown. 95 P. longipaleatum

+ Stipe scales bicolorous: brown with blackish brown centers. 96 P. nudisorum

37 (34) Stipe (at least stipe base) with blackish brown scales; rachis scales light brown (38)

+ Stipe without blackish brown scales; rachis scales grayish brown (39)

38 (37) Sori medial or close to midrib. 99 P. braunii

+ Sori marginal. 100 P. ningshenense

39 (37) Rachis scales obviously reflexed. 101 P. retrosopaleaceum

+ Rachis scales not reflexed (40)

40 (39) Rachis scales narrowly lanceolate or linear; sori medial or nearly marginal. 102 P. polyblepharum

+ Rachis (at least lower part of rachis) with ovate and ovate-lanceolate scales; sori medial, marginal, submarginal, or close to midrib (41)

41 (40) Lamina normally shorter than 45 cm; scales of upper part of rachis narrowly lanceolate; pinnules normally shorter than 1 cm. 103 P. parvipinnulum

+ Lamina normally longer than 50 cm; upper part of rachis also with ovate and ovate-lanceolate scales; pinnules up to 1.5 cm (42)

42 (41) Lamina oblong-lanceolate, ratio of length to width ca. 4; rachis scales caudate; pinnules narrowly deltoid, with numerous microscales adaxially. 104 P. sozanense

+ Lamina elliptic-lanceolate, ratio of length to width ca. 2.4; rachis scales acuminate; pinnules oblong, with few microscales adaxially. 105 P. ovatopaleaceum

List of lower taxa