Plagiochila section Peculiares

Key to the world species of Plagiochila section Peculiares

1a. Stem cortex with hyalodermis............................................................................................................................................................2

1b. Stem cortex without hyalodermis.......................................................................................................................................................3

2a. Plant 5–6 cm long, 2.8–4.5 mm wide; stem 250–300 mm in diameter, 10–16 cells across; paraphyllia present; length:breadth ratio of leaves 1.3–1.5:1, 10–15 teeth per leaf.............................................................................................................. P. caulimammillosa View in CoL

2b. Plant 2.0– 2.2 cm long, 3.5–4.0 mm wide; stem 220 mm in diameter, 9–10 cells across; paraphyllia absent; length:breadth ratio of leaves 1.6–1.7:1, 20–22 teeth per leaf ........................................................................................................................ P. hyalodermica View in CoL

3a. Leaf cells vermiculate.........................................................................................................................................................................4

3b. Leaf cells not vermiculate ..................................................................................................................................................................6

4a. Stem exposed both dorsally as well as ventrally; leaves rectangulate, length:breadth ratio of leaves 1.8–2.8:1, teeth 4–8 (-10) per leaf ............................................................................................................................................................................... P. meagheriana

4b. Stem exposed dorsally, ventral surface completely hidden; leaves broadly or triangularly ovate, length:breadth ratio of leaves 1.1–1.4:1, teeth 9–29 per leaf .............................................................................................................................................................5

5a. Plant 6–8 cm long, 3.2–4.2 mm wide, stem up to 350 μm in diameter; leaves 1.9–2.1 mm long, teeth 13–29 per leaf.. P. peculiaris View in CoL

5b. Plant 2–5 cm long, 3.0– 3.5 mm wide, stem up to 300 μm in diameter; leaves 1.2–1.5 mm long, teeth 9–18 per leaf........................ ................................................................................................................................................................................... P. philippinensis View in CoL

6a. Leaves highly fragmenting .................................................................................................................................................... P. vexans View in CoL

6b. Leaves not fragmenting as much (as P. vexans View in CoL ) .................................................................................................................................7

7a. Plants 1.0– 2.6 mm wide .....................................................................................................................................................................8

7b. Plants 2.7–5.2 mm wide ...................................................................................................................................................................11

8a. Stem surface with numerous spine-like paraphyllia on both dorsal and ventral surface ............................................ P. paraphyllosa View in CoL

8b. Stem surface smooth with lamelliform paraphyllia on the dorsal leaf base (occasionally present in P. devexa View in CoL , usually absent in P. zonata View in CoL ) ................................................................................................................................................................................................9

9a. Leaves oblong-orbicular; leaf cells with large, nodulose trigones ........................................................................................ P. devexa View in CoL

9b. Leaves broadly ovate to oblong-ovate or triangularly suborbicular; leaf cells without or with very small trigones.......................10

10a. Leaf cells without trigones, leaves broadly ovate to oblong-ovate, 1.2–1.4 mm long, 1.3–1.4 mm wide; paraphyllia rarely present; perianth campanulate, 1.2–1.6 mm long, 1.6–1.8 mm wide, with 25–28 small teeth........................................................... P. zonata View in CoL

10b. Leaf cells with small trigones, leaves triangularly suborbicular, 1.1–1.2 mm long, 0.6–0.9 mm wide; paraphyllia present at each dorsal leaf base; perianth long obovoid to cylindrical, about 1.4 mm long, 0.9 mm wide, with 14–16 small teeth.............. P. zangii View in CoL

11a. Leaves distinctly wider than long, length:breadth ratio of leaves less than 1 ....................................................................... P. magna View in CoL

11b. Leaves distinctly longer than wide, length:breadth ratio of leaves 1 or more than 1.......................................................................12

12a. Plants with paraphyllia .....................................................................................................................................................................13

12b. Plants without paraphyllia ................................................................................................................................................................16

13a. Leaves broadly ovate or suborbicular; female bracts 3.5–4 mm long, 3–5 mm wide; perianth much longer, 6 mm long, 2.5 mm wide .................................................................................................................................................................................... P. renitens View in CoL

13b. Leaves oblong-ovate; female bracts 1.7–3.4 mm long, 1.3–2.8 mm wide; perianth much longer, 1.1–4.8 mm long, 0.8–1.9 mm wide ..................................................................................................................................................................................................14

14a. Paraphyllia 1(-2) per leaf base, entire, lamelliform; stem 12–20 cells across diameter, 150–260 × 230–420 μm; teeth (6-)7–20(-22) per leaf; gynoecia mostly without, or rarely with 1, small subfloral innovation; bracts 1.7–2.1 mm long, 1.3–1.9 mm wide, with 5–21 teeth per bract; perianth 1.1–2.6 mm long, 0.8–1.3 mm wide, dorsal keel unwinged ................................... P. arunachalensis View in CoL

14b. Paraphyllia (1-)2–3 per leaf base, entire, lamelliform or dentate, stem up to 27 cells across in diameter, 280-330 μm in diameter; teeth (10-)22–28(-36) per leaf; gynoecia with 1–2 innovations; bracts 2.4–3.1 mm long, 1.9-2.8 mm wide, with 24–37 teeth per bract; perianth 3.5–4.8 mm long, 1.4–1.9 mm wide, dorsal keel often narrowly winged................................................................15

15a. Leaves oblong-ovate, persistent; propagules absent ...................................................................................... P. durelii subsp. durelii View in CoL

15b. Leaves orbicular to oblong-ovate, fragmenting; propagules present ................................................... P. durelii subsp. guizhouensis View in CoL

16a. Leaves with 6–18 teeth per leaf........................................................................................................................................................17

16b. Leaves with 12–26(-38) teeth per leaf..............................................................................................................................................18

17a. Plants 2.6–3.3 mm wide; stem 285–300 μm in diameter; leaves 1.3–1.5 mm long, 0.6–0.8 mm wide, length:breadth ratio usually 2; gynoecia without innovation ............................................................................................................................................. P. grollei View in CoL

17b. Plants 3.5–4.8 mm wide; stem 330–350 μm in diameter; leaves 1.5–1.8 mm long, 1.2–1.5 mm wide, length:breadth ratio usually up to 1.3; gynoecia with 2 innovations....................................................................................................................... P. pseudopoeltii View in CoL

18a. Plants 10–30 mm long, 1.8–2.1 mm wide; stem 240–260 × 165–175 μm; leaves ovate, 1.0– 1.4 mm long, 0.7–1.0 mm wide; female bracts 1.4–1.6 mm long, 1.0– 1.1 mm wide; perianth long, narrowly cylindrical, obovate, 2.4–2.8 mm long and 0.8–1.0 mm wide ........................................................................................................................................................................................... P. alaskana

18b. Plants 30–60 mm long, 2.8–5.2 mm wide; stem 250–400 μm in diameter; leaves broadly oblong-ovate to orbicular, 1.2–3.5 mm long, 0.8–2.8 mm wide; female bracts 2.2–3.3 mm long, 1.4–3.1 mm wide; perianth long, cylindrical, 3.3–5.2 mm long and 1.2–1.7 mm wide ..............................................................................................................................................................................19

19a. Plants 40–60 mm long, 4.4–5.2 mm wide; geotropic flagella present; rhizoids scanty on aerial shoots; dorsal stem surface almost hidden, ventral surface completely hidden, stem 350–400 μm in diameter; leaves 2.4–3.5 mm long, 2.1–2.8 mm wide, trigones acute; female bracts 3.1–3.3 mm long, 2.2–3.1 mm wide; perianth 4.5–5.2 mm long and 1.5–1.7 mm wide ............... P. perserrata View in CoL

19b. Plants 30–40 mm long, 2.8–4 mm wide; geotropic flagella absent; rhizoids numerous on ventral surface of aerial shoots, sometimes even on dorsal surface; dorsal stem surface sometimes exposed, ventral surface partially hidden, stem 250–330 μm in diameter; leaves 1.2–2.1 mm long, 0.8–1.2 mm wide, trigones absent; female bracts 2.2–2.8 mm long, 1.4–2.2 mm wide; perianth 3.3–4.5 mm long and 1.2–1.7 mm wide................................................................................................................................. P. semidecurrens View in CoL