Macromitrium, BRID. IN

Li, Dandan, Li, Yuehan, Ren, Yan, Liu, Shutong, Yu, Jing & Guo, Shuiliang, 2024, Three new synonyms of Macromitrium japonicum Dozy & Molk. (Bryophyta, Orthotrichaceae) based on morphological and molecular evidence, Cryptogamie, Bryologie 20 (3), pp. 23-36 : 33

KEY OF MACROMITRIUM BRID. IN CHINA AND JAPAN

1. Peristome absent ............................................................................................................................................. ...... M. formosae Cardot , M. gymnostomum Sull. & Lesq. , M. holomitrioides Nog. , M. ousiense Broth. & Paris , M. taiheizanense Nog. , M. tuberculatum Dixon

— Peristome present ........................................................................................................................................ 2

2. Laminae of branch leaves irregular 1-3-stratose proliferation with pluripapillose cells ..................................... ......................................................................................................... M. nepalense (Hook. & Grev.) Schwägr.

— Laminae of branch leaves unistratose or partially bistratose in median and upper portions .......................... 3

3. Laminae of branch leaves partially bistratose in median and upper portions ................................................... .................................................................................... M. maolanense Ze Y. Zhang, D.D.Li, J.Yu & S.L.Guo

— Laminae of branch leaves unistratose ........................................................................................................... 4

4. All cells of branch leaves clear and smooth ..................................................................................................... .............................................................. M. microstomum (Hook. & Grev.) Schwägr. , M. cuspidatum Hampe

— Cells of branch leaves papillose (mammillose or conic-bulging) to varying degrees ...................................... 5

5. Seta rather short, often 0.3-0.7 mm ............................................................. M. hainanense S.L.Guo & S.He

— Seta relatively longer, often longer than 2.0 mm .......................................................................................... 6

6. Upper cells of branch leaves with a single large linear central papilla up to 14-18 µm high ............................. ...................................................... M. longipapillosum D.D.Li, J.Yu, T.Cao & S.L.Guo , M. taiwanense Nog.

— Upper cells of branch leaves often pluri-papillose to varying degrees or conic bulging and mammillosum ... 7

7. Calyptrae smooth and naked .......................................................................................................................... M. blumei var. zollingeri (Mitt. ex Bosch & Sande Lac.) S.L.Guo, B.C.Tan & Virtanen , M. macrosporum Broth.

— Calyptrae hairy ............................................................................................................................................ 8

8. Median and upper laminal cells mammilate (conic-bulging with a blunt central projection) .......................... ............................................................................................. M. uraiense Nog. , M. fortunatii Cardot & Thér.

— Median and upper laminal cells pluripapillose to varying degrees ................................................................ 9

9. Setae shorter than 2.0 mm, branch leaves with linear and smooth basal cells, sporophytes slightly exserted the perichaetial leaves ......................................................................................................... M. prolognatum Mitt.

— Setae often longer than 3.0 mm, branch leaves with papillose cells to varying degrees, sporophytes obviously exserted the perichaetial leaves ................................................................................................................... 10

10. Basal cells of branch leaves often papillose to varying degrees ........................... M. cavaleriei Cardot & Thér. , M. ferriei Cardot & Thér. , M. quercicola Brotherus , M. tosae Besch. , M. turgidium Dixon

— Basal cells of branch leaves smooth, without papillae ................................................................................. 11

11. Apices of branch leaves spreading when moist, calyptrae with long and brown-yellowish hairs ....................... .......................................................................................................................................... M. comatum Mitt.

— Apices of branch leaves often adaxially incurved and inrolled when moist, caplyptrae with yellowish hairs ..... ......................................................................................................................... M. japonicum Dozy & Molk.