BRYACEAE RCHB.

Spence, John R., 2022, Studies in Austral Bryaceae (Bryopsida). IV. New records from the Falkland Islands (Islas Malvinas), with a phytogeographic analysis of the family, Cryptogamie, Bryologie 20 (15), pp. 211-224 : 217-219

KEY TO BRYACEAE RCHB. OF THE FALKLAND ISLANDS

1. Plants very small, stems to 1 cm, strongly julaceous, leaves mostly <1 mm long, costa weak, not reaching apex, leaf tip rounded-obtuse, with or without short apiculus, proximal laminal cells quadrate ............................. 2

— Plant sizes from small to large, stems 1-10 cm, not or weakly julaceous, leaves mostly (1.5-) 2-8 mm, costa variable, from not reaching apex to percurrent or excurrent in short to long awn, tips obtuse to acuminate, apiculus lacking, if plants small and julaceous, proximal laminal cells elongate rectangular across leaf base or in alar region ........................................................................................................................................................... 3

2. Plants silver-green, distal lamina cells elongate, length 3-5:1, apiculus sometimes present; leafy bulbils sometimes present in leaf axils ................................................................................................... Bryum argenteum Hedw.

— Plants bright green, distal lamina cells short and wide, 2-3:1, apiculus and bulbils absent .............................. ......................................................................................................................... Bryum microimbricatum Ochi

3. Plants robust, stems long, to 10 cm, evenly foliate, leaves ovate, to 8 mm long, limbidium present, distal leaf margins sharply dentate, stolons sometimes present ......... Rhodobryum cf. roseodens (Müll.Hal. ex Geh.) Paris

— Plants mostly smaller, stems short or to 4-6 cm long, leaves mostly <5 mm, limbidium present or absent, distal leaf margins smooth to serrate, stolons absent .............................................................................................. 4

4. Plants distinctly rosulate, rarely two or more interrupted rosettes present, leaves flaring in rosette when wet, strong limbidium present, distal lamina margins serrulate to serrate, rhizoidal tubers often present .............. 5

— Plants evenly foliate, gemmiform to short-comose with leaves mostly erect spreading when wet, limbidium present or absent, distal leaf margins smooth or serrulate, rhizoidal tubers sometimes present ...................... 8

5. Leaves 2-3 mm long, spirally twisted around stem when dry, costa excurrent in long awn .............................. ...................................................................................................... Rosulabryum capillare (Hedw.) J.R.Spence

— Leaves 3-5 mm long, somewhat imbricate to irregularly contorted when dry, costa excurrent in short awn .. 6

6. Leaf limbidium very strong, 4-6 rows wide, whitish, stems sometimes in two or more interrupted rosettes .... .................................................................................................... Rosulabryum perlimbatum (Cardot) Ochyra

— Leaf limbidium narrow, 2-3 rows wide, same color as lamina, stems usually in single rosettes ....................... 7

7. Leaves sometimes appressed-imbricate when dry, ovate, distal lamina margins serrulate ................................. ................................................................................... Rosulabryum macrophyllum (Cardot & Broth.) Ochyra

— Leaves contorted and twisted when dry, not imbricate, obovate to spathulate, distal lamina margins sharply serrate .................................................................................... Rosulabryum billardierei (Schwägr.) J.R.Spence

8. Plants small, stems to 2 cm, leaves mostly <2 mm long, costa not reaching apex to short-excurrent in awn, bulbils present in leaf axils of sterile stems .................................................................................................... 9

— Plant sizes various, stems to 6 cm, leaves often> 2 mm long, costa variable, not reaching apex to excurrent in long awn, bulbils absent ............................................................................................................................. 11

9. Bulbils small, ovate, 200-450 µm long, typically (2-)3-5 or more per leaf axil, costa variable, percurrent to short excurrent, some leaves with longer excurrent awn sometimes present ... Bryum barnesii J.B.Wood ex Schimp.

— Bulbils large, to 1 mm, typically 1(-3) present in leaf axils, costa not reaching apex to short excurrent in short awn ............................................................................................................................................................ 10

10. Leaves ovate, costa weak, not reaching apex to percurrent, lamina cells in alar regions elongate-rectangular, bulbils long and narrow, to 1 mm, often 2 or 3 present, club-shaped, leafy primordia restricted mostly to top of bulbil, often flaring out in rosette ........................................................................... Bryum miserum Cardot

— Leaves ovate to ovate-lanceolate, costa mostly percurrent to short-excurrent in awn, lamina cells in alar region quadrate, bulbils broadly ovate to pyriform, to 750 µm, mostly single, leafy primordia not restricted to apex of bulbil, often arising from mid-bulbil or lower ....................................................... Bryum dichotomum Hedw.

11. Rhizoidal tubers commonly present in sterile collections, mostly on rhizoids arising at base of stem and in soil ............................................................................................................................................................. 12

— Rhizoidal tubers absent .............................................................................................................................. 14

12. Leaves slender, ovate to ovate-lanceolate, much longer than wide, apex acute to acuminate, costa distinctly excurrent in short to medium-length awn, distal lamina cells longer than proximal cells, tubers pyriform to spherical, orange to red, mostly <300 µm in widest dimension ................................................................................. 13

— Leaves broadly ovate, not much longer than wide, apex broadly rounded, costa not reaching apex, distal lamina cells short and wide, proximal cells much longer, rhizoidal tubers irregularly spherical to sometimes flattened and lobed, brown to red-brown ....................................................................... Bryum gilliesii Hook. (in part)

13. Sexuality synoicous, rhizoidal tubers small, pyriform, orange, <100 µm in longest axis .................................. .......................................................................................................................... Bryum pabstianum Müll.Hal.

— Sexuality dioicous, rhizoidal tubers larger, spherical, red, to 300 µm wide ...................................................... .................................................................................................. Imbribryum subapiculatum Cardot & Broth.

14. Costa strong, excurrent in medium to distinctly long awn, plants mostly small, in compact tufts, stems gemmiform to short-comose (leaves enlarged towards stem tip but not flaring in rosette), mostly <2 cm long ..... ................................................................................................................................................................... 15

— Costa not reaching apex, percurrent or very short-excurrent in short awn, plants evenly foliate, weakly julaceous, to comose, stems often longer than 2 cm .................................................................................................... 19

15. Sexuality dioicous, awns very long, often> ½ lamina length, sometimes denticulate, limbidium weak or absent, spores mostly <15 µm ............................................................................................................................... 16

— Sexuality autoicous or synoicous, awns medium length to long, mostly <½ lamina length, limbidium present, narrow to wide; spores mostly>15 µm ...................................................................................................... 17

16. Leaves with very long awns, ½-1/1 length of lamina, denticulate, distal lamina cells 3-4:1, short fragile innovations in leaf axils absent ................................................................................... Bryum badium Bruch ex Brid.

— Leaves awns shorter, mostly ½ lamina length, smooth, distal lamina cells long, 4-6:1, fragile innovations with rudimentary leaves common in leaf axils ............................................................... Bryum caespiticium Hedw.

17. Sexuality autoicous, leaves 2-3 mm long, ovate-lanceolate to lingulate, stems short-comose, somewhat enlarged towards stem tip, peristome well developed, cilia present, spores 14-20 µm, capsules long pyriform to clavate ............................................................................ Ptychostomum pallescens (Schleich. ex Schwägr.) J.R.Spence

— Sexuality synoicous, leaves mostly <2 mm long, ovate-lanceolate, stems short and compact, usually somewhat gemmiform, peristome reduced, cilia absent or short, spores>20 µm, capsules pyriform ............................ 18

18. Endostome often adherent to exostome at base, exostome teeth with chambered look of patchy cells with crosswalls, cilia absent or very short, spores 22-35 µm, variable in size but often> 30 µm ..................................... ................................................................................................................ Ptychostomum compactum Hornsch.

— Endostome and exostome free, teeth not chambered or patchy, cilia short, sometimes 1-2 longer ones present, spores 22-26 µm ..................................................................................... Ptychostomum inclinatum Hornsch.

19. Plants consisting mostly of masses of slender brown to red-green innovations, leaves ovate, concave, limbidium weak to absent, brown to red-brown filiform gemmae present in leaf axils ...................................................... ....................................................................................................... Rosulabryum flaccidum (Brid.) J.R.Spence

— Plants not or rarely dominated by innovations, leaves lanceolate, ovate, ovate-lanceolate or suborbicular, concave or flat, limbidium present or absent, filiform gemmae absent ..................................................................... 20

20. Plants large, stems to 4 cm, often matted with rhizoids, leaves 3-4 mm long, ovate, distinctly strongly decurrent, apex acute, limbidium distinct ....................................................................................................................... ..................... Ptychostomum pseudotriquetrum (Hedw.) J.R.Spence & H.P.Ramsay ex Holyoak & N.Pedersen

— Plants mostly smaller, stems rarely to 3 cm, leaves 1-3(-4) mm, lanceolate, ovate, or suborbicular, not or weakly decurrent, apex rounded obtuse to acute or rarely acuminate, limbidium present or absent ........................ 21

21. Plants small, leaves mostly <1(-2) mm, narrowly lanceolate, costa weak, not reaching apex, limbidium absent ............................................................................................................. Bryum rhizoblastum Cardot & Broth.

— Plants small to large, leaves 2-3 mm, ovate to suborbicular, costa variable, not reaching apex, percurrent to short excurrent, limbidium present or absent ...................................................................................................... 22

22. Stems gemmiform, forming pale whitish-green to yellow-green budlike shoots, leaves strongly concave, ovate, limbidium weak or absent, costa short excurrent as stout awn, basal lamina cells shorter than distal cells, often forming small pale quadrate group in alar region ........................................................ Bryum funkii Schwägr.

— Stems elongate, evenly foliate to julaceous, or sometimes comose, not bud-like, leaves flat or concave, ovate to suborbicular, limbidium present or absent, costa not reaching apex to short excurrent, basal lamina cells longer or shorter than distal cells, alar region not distinct ...................................................................................... 23

23. Stems evenly foliate to somewhat comose, distal lamina cells shorter and often wider than proximal cells, rhomboidal, proximal cells more or less rectangular, limbidium present .............................................................. 24

— Stems more or less julaceous or evenly foliate, distal lamina cells longer than proximal cells, often oblique to costa, proximal cells mostly quadrate to short-rectangular, limbidium absent or weak ................................ 25

24. Stems elongate and evenly foliate, leaves ovate, not decurrent, flat or weakly concave, costa excurrent in short awn, sexuality autoicous, peristome reduced, endostome adherent to exostome, cilia lacking, spores 22-26 µm ......................................................... Ptychostomum gayanum (Mont. ex Müll.Hal.) Ochyra & Bedn. -Ochyra

— Stems short, somewhat comose, leaves broadly ovate to suborbicular, somewhat decurrent, distinctly concave, costa mostly not reaching apex or percurrent, sexuality unknown, capsules unknown .................................... .............................................................................................................. Bryum sabuletorum Cardot & Broth.

25. Plants green to olive, julaceous, large, stems to 6 cm, leaves to 4 mm, obtuse to broadly acute, costa percurrent or sometimes weaker, distal lamina cells incrassate, somewhat vermicular, 3-4:1, oblique to costa c. 30-45° ......................................................... Imbribryum laevigatum (Hook.f. & Wilson) J.R.Spence & H.P.Ramsay

— Plants green, yellow-green, red or brown, smaller, stems <3 cm, leaves 1-3 mm, acute to obtuse, costa not reaching apex, percurrent or short-excurrent in awn, distal lamina cells not or rarely oblique to costa, mostly thin-walled ................................................................................................................................................. 26

26. Stems somewhat julaceous, leaves small, to 1 mm, brown-yellow to brown-green, leaf base red ...................... ...................................................... Plagiobryoides orbiculatifolia (Cardot & Broth.) Ochyra & Bedn. -Ochyra

— Stems evenly foliate but not julaceous, leaves mostly somewhat shrunken-contorted when dry, yellow, yellowgreen to red, leaf base same color as rest of lamina ...................................................................................... 27

27. Plants green to yellow-green, leaves more or less flat, ovate to sometimes lingulate, weak limbidium present to mid-leaf, costa percurrent to short-excurrent in awn, distal cells somewhat thick-walled but not incrassate, rarely oblique to costa, capsule long-clavate, to 5 mm, often curved, often purple when mature ............................................................................ Imbribryum clavatum (Schimp.) J.R.Spence & H.P.Ramsay

— Plants green to red, leaves somewhat concave, ovate, limbidium absent, costa not reaching apex to short-excurrent, distal cells mostly thin-walled, not oblique to costa, capsules pyriform to long-necked with somewhat inflated urn, mostly <3 mm, brown at maturity ..................................................................................................... 28

28. Plants small, stems short, mostly <1.5 cm, leaves mostly <2 mm, often red-tinted, apex more or less roundedobtuse, costa not reaching apex ....................................................................... Bryum gilliesii Hook. (in part)

— Plants larger, stems to 3 cm, leaves 2-3 mm, green to yellow-green, apex acute, costa percurrent to short-excurrent in awn .............................................................................................................. Bryum platyphyllum Schwägr.