Macromitrium undetermined

Thouvenot, Louis, 2019, A review of the genus Macromitrium Brid. (Orthotrichaceae, Bryophyta) in New Caledonia, Cryptogamie, Bryologie 20 (16), pp. 167-217 : 176-177

KEY TO THE MacROMiTRiUM BRID. SPECIES IN NEW CALEDONIA

1. Branch leaves long aristate, aristae ≥ 0.1 mm long ....................................................................................... 2

— Branch leaves muticous, apiculate or mucronate, if aristate, aristae <0.1 mm long ...................................... 7

2. Small species, most branches less than 10 mm long (with respect to the most developed, mainly fertile branches) ..................................................................................................................................................... 3

— Larger species, most branches more than 10 mm long (condition as above) ................................................. 4

3. When dry, branches fusiform, leaves carinate, tightly spirally coiled ................................. M. panduraefolium

— When dry, branches shaggy, leaves soft, unevenly erect-patent .............................................. M. humboldtense

4. Leaves smooth thorough, lanceolate, long narrowed into asymmetrical acumina ......................... M. larrainii

— Leaves papillose, lanceolate to ligulate, acute to obtuse-rounded .................................................................. 5

5. Aristae reddish, at least some over 0.5 mm long, leaves ligulate with obtuse to rounded apices ....................... ................................................................................................................................................... M. rufipilum

— Aristae variously coloured, less than 0.3 mm long, leaves lanceolate with acute to narrowly obtuse apices ...... .................................................................................................................................................................... 6

6. Leaves narrowly lanceolate to sub-triangulate, narrowed from shortly above the bases into long narrow acumina ......................................................................................................................................................... ...................................................................................................................................................... M. cardotii

— Leaves lanceolate, widest above ¹⁄₅ leaf length above the base, with wider acumina, abruptly acute ................. ............................................................................................................... M. pulchrum var. pulchrum pro parte

7. Plants small, branches ≤ 12 mm long (with respect to the most developed, mainly fertile branches) ............ 8

— Plant medium to large, branches> 12 mm long (condition as above) ........................................................ 20

8. Upper part of leaves multi-layered, at least in patches or in the apices, superficial cells rounded and pluripapillose ............................................................................................................................................... M. tongense

— Leaves single-layered thorough .................................................................................................................... 9

9. Leaves tongue-like, apices rounded to truncate, fusiform gemmae present on leaves, calyptrae naked, branches ≤ 3mm long .............................................................................................................................. M. brevicaule

— Leaves oblong, lanceolate to ligulate, apices acute to obtuse, gemmae absent, calyptrae hairy, sometimes rarely so, branches> 3 mm ................................................................................................................................. 10

10. Setae shorter <1.5(-2) mm long ................................................................................................................ 11

— Setae longer> 2 mm long .......................................................................................................................... 13

11. Leaves ligulate, basal cells short, c. 2 × longer than wide, smooth, vaginulae naked, branches ≤ 5 mm long; rare plant from lowest altitudes .................................................................................................. M. brachypodium

— Leaves oblong to lanceolate, a few basal cells longer, at least 3 x longer than wide, someone papillose, vaginulae long hairy, normal branches 5-7 mm long; plants frequent at all altitudes ................................................. 12

12. When dry, branches curly, twisted leaves loosely erect with incurved to circinate apices directed to the side, in wet condition leaves erect-patent .................................................................................................... M. francii

— When dry, branches funiculate, leaves erect to appressed, incurved apices adaxially directed, the upper ones somewhat twisted, in wet condition leaves spreading recurved ..................................................... M. pilosum

13. Branches funiculate when dry, with leaves spirally coiled, apices straight or slightly incurved .................... 14

— Branches not funiculate when dry, with leaves unevenly erect-patent, individually twisted, apices incurved to circinate .................................................................................................................................................... 15

14. Branches thin, regularly rope-like, leaves twisted together, arranged in bands spirally coiled around the branches, upper cells smooth, setae long, 5-30 mm long, calyptrae naked, plants frequent at all altitudes ...................... ............................................................................................................................................. M. microstomum

— Branches short, not so thin, leaves individually coiled around the branches, upper cells papillose, setae short, <5 mm long, calyptrae hairy, rare lowland species ............................................. M. aurescens var. caledonicum

15. Upper cells smooth, arranged in continuous longitudinal rows, setae long up to 25 mm long ................... 16

— Upper cells papillose or, if smooth, not in continuous longitudinal rows, setae shorter ≤ 7 mm long ......... 17

16. Calyptrae and vaginulae hairy, lower cells smooth or with a few single low papillae .................... M. renauldii

— Calyptrae and vaginulae naked, lower cells with numerous single high papillae ............................. M. taoense

17. Leaves long ligulate, obtuse apiculate, 1.2-1.8 mm long, elongate basal cells few with single papillae scarce, branches short, 2-4(-5) mm long .......................................................................................... M. ligulaefolium

— Leaves not long ligulate, elongate basal cells few or not, with many single papillae, branches short to medium, 3-6(-10) mm long ..................................................................................................................................... 18

18. Setae longer, ≥ 15 mm ............................................................................ M. pulchrum var. pulchrum pro parte

— Setae shorter, <10 mm .............................................................................................................................. 19

19. Calyptrae very hairy, basal hairs wide spreading, leaves ≤ 1.3 mm long, broadly ligulate to short lanceolate, basal cells with wide straight lumina .............................................................................................. M. orthostichum

— Calyptrae with scarce erect hairs, leaves 1.4-2.4 mm long, leaf lower half wide oblong, upper half ligulate to lanceolate, basal cells very thick walled with sinuous or straight narrow lumina .............................................. ......................................................................................................................... M. hemitrichodes var. sarasinii

20. Lower cells short rectangular or with a few ranks of longer cells at base ..................................................... 21

— Long lower cells occupying a conspicuous 1/3 leaf length .......................................................................... 22

21. Capsule with erect rim, peristome present, branches medium sized up to 10-15 mm long ............................. ........................................................................................................... M. involutifolium subsp. involutifolium

— Capsule with collapse rim, peristome absent, branches longer, up to 30 mm long .......................................... ........................................................................................................ M. involutifolium subsp. ptychomitrioides

22. Lower cells smooth .................................................................................................................................... 23

— Lower cells papillose .................................................................................................................................. 25

23. Leaves medium, ≤ 1.7 mm long, upper laminae shortly narrowed in obtuse to acute apices ..... M. laevigatum

— Leaves longer,> 1.7 mm long, upper laminae progressively narrowed in a very long and narrow acumen .. 24

24. Calyptrae naked, apices of vegetative leaves partly bi-layered, frequent species ................................. M. leratii

— Calyptrae sparsely hairy, apices of vegetative leaves single layered thorough, rare plant ............. M. salakanum

25. Leaves narrowly lanceolate to sub-triangular, progressively narrowed from shortly above the base, acumina very narrow ........................................................................................................................................... M. cardotii

— Leaves lanceolate to lanceolate-ligulate, widest at ¹⁄₅ leaf length or more above the base ............................. 26

26 – Leaves erect-patent in moist condition, leaf apices narrowly obtuse to acuminate, short aristate to muticous, branches simple or rarely furcate ............................................................ M. pulchrum var. pulchrum pro parte

— Leaves spreading-recurved when moist, leaf apices obtuse to rounded, mucronate or not, branches with fastigiated branchlets ............................................................................................ M. pulchrum var. neocaledonicum