The liverwort genera (Bryophyta: Hepaticae and Anthocerotae) of Britain and Ireland

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L. Watson and M. J. Dallwitz

Character list


#1. <English names>/

It seems these they have yet to be invented to satisfy modern bureaucratic regulations for conservation-related publications.

#2. ~ <Sensu lato genus to which sometimes referred (see Notes)>/

Mostly via cross referencing with Macvicar (1926).

#3. Including <generic names treated here as synonyms (see Notes)>/


#4. Plants <leafy or thalloid>/

1. leafy/

2. thalloid, not leafy/

3. thalloid, with a short, basal, cylindrical tuberous portion obliquely embedded in the substrate, preceding a prostrate, fan-like winged exension with a semi-circular midrib and erect, unistratose dorsal lamellae radiating from the midrib to the wing margins/

#5. <Leafy: branching details>/

#6. The stems <leafy, whether branching>/

1. branching/

2. simple/

#7. The branching <leafy, position>/

1. dorsal/

2. ventral/

3. lateral/

4. apical/

#8. The branching <leafy, whether dichotomous>/

1. dichotomous/

2. not dichotomous <implicit>/

#9. The branching <leafy, type>/

1. of the Frullania type <the branches arising terminally, with each replacing the ventral lobe of its associated leaf>/

2. of the Lejeunea type <each branch arising immediately behind the ventral base of a leaf>/

3. of the Radula type <each branch ariseing slightly in front of a leaf base on the ventral side of the stem, and usually less vigorous than the main axis>/

4. conventional <not of Frullania, Lejeunea or Radula type: implicit>/

#10. The stems <leafy: tissue differentiation>/

1. with <usually thin-walled> cortical cells clearly differentiated from the <usually smaller, thicker walled> cells of the central strand/

2. with no clear differentiation of cortical and central tissues/

#11. The stems <leafy, whether translucent>/

1. translucent/

2. not translucent <to become implicit>/

#12. Plants <leafy, presence of flagelliform shoots>/

1. with flagella or flagelliform shoots or branches/

2. with neither flagella nor flagelliform shoots or branches <implicit>/

Flagellum: a slender branch with or without vestigial leaves, bearing rhizoids.

Flagelliform: of a leafy stem or branch which is distally attenuated and flagella-like.

#13. Plants <leafy, presence of paraphyllia>/

1. with paraphyllia amongst the leaves/

2. without paraphyllia <implicit>/

Paraphyllia: simple or branched, ciliate or lamellate appendages scattered among the stem leaves.

#14. <Acrogynous or anacrogynous>/

1. acrogynous <acrogenous: archegonia and sporophytes or female receptacles terminating axes, resulting in sympodial growth>/

2. anacrogynous <anacrogenous: archegonia and sporophytes or female receptacles arising from behind the apical cell, dorsal or only ostensibly terminal, growth generally monopodial>/

Acrogynous (acrogenous): archegonia and sporophytes or female receptacles terminating axes, resulting in sympodial growth.

anacrogynous (anacrogenous): archegonia and sporophytes or female receptacles arising from behind the apical cell, dorsal or only ostensibly terminal, generally resulting in monopodial growth.

#15. The leaf cells <all forms, presence of trigones>/

1. with trigones/

2. without trigones/

Trigones: wall thickenings a the angles of cells.

#16. The leaf cells <whether mamillose>/

1. conspicuously mamillose/

2. smooth, not mamillose <implicit>/

Mamillose: referring to a nipple-like projection from the epidermis.

#17. Rhizoids <all forms, presence>/

1. present <implicit>/

2. absent/

#18. Rhizoids <colour>/

1. colourless <hyaline>/

2. violet or purple/

3. brown/

#19. Rhizoids <all smooth, or smooth and tuberculate>/

1. of one kind, all smooth <tuberculate rhizoids absent: implicit>/

2. of two kinds, smooth and tuberculate <tuberculate rhizoids present>/

Tuberculate rhizoid: a rhizoid with papilla-like projections from the inner walls.

#20. The leafy shoots <symmetry>/

1. radially symmetrical, with three ranks of similar and more or less equal sized leaves <isophyllous>/

2. dorsiventral, with two equal ranks of lateral leaves and a third, ventral rank of <more or less> smaller underleaves <anisophyllous>/

3. dorsiventral, with the two ranks of laterals more or less equal in size <isophyllous> and the ventral rank lacking/

4. more or less dorsiventral, the three-ranked leaves more more less equal in size <isophyllous>/

5. not dorsiventral, with two equal ranks of similar lateral leaves and ventral leaves lacking/

#21. The leafy shoots <whether julaceous>/

1. julaceous/

2. not julaceous <implicit>/

Julaceous: of shoots that appear cylindrical and worm-like, owing to tightly appressed, imbricate leaves.

#22. The vegetative leaves <symmetry>/

1. more or less symmetrical/

2. markedly asymmetrical/

#23. The vegetative leaves <shape detail>/

1. wedge-shaped/

2. not wedge-shaped/

#24. The vegetative leaves <insertion>/

1. transversely inserted/

2. obliquely inserted/

3. <more or less longitudinal,> with J-shaped insertion/

4. sub-transversely inserted, the dorsal half more or less transverse, the ventral half oblique/

#25. The vegetative leaves <opposite or alternate>/

1. opposite/

2. alternate/

#26. The vegetative leaves <overlapping or distant>/

1. overlapping <or imbricate, at least the distal ones>/

2. distant/

#27. The <overlapping, lateral> vegetative leaves <incubous or succubous>/

1. incubous <with the forward margin of each leaf overlying the hind margin of the leaf in front>/

2. succubous <with the forward margin of each leaf overlapped by the hind margin of the leaf in front>/

Incubous: of a leafy stem with leaves arranged such that the forward margin of each overlaps the rear margin of the one immediately distal to it on the same side. Contrast with succubous, where the hind margin of each leaf overlaps the forward margin of the one behind it. Applicable to stems with leaves that are more or less obliquely to longitudinally inserted and overlapping.

#28. The <vegetative> leaf margins <entire or toothed>/

1. toothed/

2. entire/

#29. The <vegetative> leaf margins <entire or toothed>/

1. multi-ciliate/

2. not multi-ciliate/

#30. The <vegetative> leaf margins <whether flat>/

1. incurved or inflexed/

2. flat/

3. deflexed/

#31. The <vegetative> leaf margins <whether decurrent>/

1. dorsally decurrent/

2. not or only slightly dorsally decurrent/

#32. The vegetative leaves <form>/

1. undivided <simple, not lobed>/

2. <primarily> bilobed/

3. <primarily> several-lobed <3–5>/

4. so deeply divided as to be almost reduced to long, slender, bi- to uniseriate segments/

#33. The <bilobed> vegetative leaves <whether complicate-bilobed>/

1. complicate-bilobed <bilobed more or less to the base into quite different dorsal and ventral lobes>/

2. not complicate-bilobed <the lobes more or less similar in size and form>/

Complicate-bilobed: of bilobed leaves having the lobes closely folded together, with the antical (dorsal) lobe lying over the postical (ventral) lobe or lobule and usually (i.e., except when the lobule is helmet-shaped) with their adaxial surfaces facing each other.

#34. The <vegetative, lobed> leaves <whether keeled>/

1. keeled proximally to the lobes/

2. not keeled/

#35. The ventral <postical> lobes <of bilobed vegetative leaves, size relative to the dorsal lobes>/

1. larger than the dorsal lobes/

2. similar in size to the dorsal ones/

3. much smaller than the dorsal ones/

#36. The ventral lobes <of bilobed vegetative leaves, whether helmet-shaped>/

1. mostly helmet-shaped or saccate/

2. neither helmet-shaped nor saccate <implicit>/

#37. The ventral <leaf> lobes <of vegetative, lobed leaves, whether bearing a stylus>/

1. with a stylus/

2. without a stylus <implicit>/

Stylus: a small awl-like, narrow or flattened structure associated with the base of a ventral leaf lobe.

#38. The vegetative leaves <presence of vittae>/

1. with vittae <a median band of longitudinally elongated cells>/

2. without vittae <implicit>/

Vitta: a band comprizing one or more rows of longitudinally elongated and thickened cells in a leaf.

#39. The vegetative leaves <presence of waxy cuticle>/

1. with a waxy cuticle/

2. without a waxy cuticle <implicit>/

#40. Underleaves <presence, conspicuousness>/

1. similar in size to the laterals/

2. smaller than the laterals though well developed and conspicuous/

3. present but much reduced or vestigial/

4. absent/

#41. Underleaves <whether bilobed>/

1. bilobed/

2. not bilobed/

#42. The <underleaf> lobes <divergence>/

1. widely divergent/

2. not divergent/

#43. The <underleaf> lobes <size and shape>/

1. acuminate, only two cells wide at the bases/

2. rounded, 4–6 cells wide at their bases/

#44. Underleaves <when present, comments>/

#45. The cells of the gametophyte <all forms, form of chlorolasts>/

1. each with a single, large chloroplast/

2. with numerous small chloroplasts/

3. lacking chloroplasts/

#46. The chloroplast-containing cells <all forms, presence of oil bodies>/

1. with conspicuous <refractory> oil bodies/

2. without oil bodies/

#47. The thallus <whether dichotomously branching>/

1. simple/

2. pinnately branching/

3. palmately branching/

4. branching dichotomously/

5. irregularly lobed <multistratose in the middle and becoming unistratose in the lobes>/

#48. <Whether subterranean>/

1. subterranean, under humus, leaf litter, etc./

2. not subterranean <implicit>/

#49. The thallus <whether greasy in appearance>/

1. greasy in appearance/

2. not greasy in appearance <implicit>/

#50. The thallus <whether hairy both dorsally and ventrally>/

1. very hairy both dorsally and ventrally/

2. not hairy both dorsally and ventrally/

#51. The thallus <presence of longitudinal conducting strand>/

1. with a conspicuous median <longitudinal> conducting strand/

2. without a conspicuous <median longitudinal> conducting strand/

#52. The thallus <presence of ventral scales>/

1. with ventral scales/

2. without ventral scales/

#53. Gemmae <all forms, presence>/

1. common/

2. rare/

3. absent/

Gemma(e): vegetative propagules borne on leaves, stems or thalli.

#54. The thallus <presence of gemma-cups>/

1. with gemma-receptacles on the surface/

2. without gemma-receptacles <on the surface>/

#55. The gemma receptacles <thalloids, form>/

1. semi-lunar with entire margins/

2. cup-shaped with frilled margins/

#56. Gemmae <forms(s) and details>/

#57. The thallus <presence of pores>/

1. with conspicuous dorsal pores/

2. with inconspicuous dorsal pores/

3. without dorsal pores/

#58. The <thallus> pores <simple or complex>/

1. simple/

2. complex/

#59. The thallus <presence of air chambers>/

1. containing conspicuous cavities/

2. without <conspicuous> cavities/

#60. The air chambers <of the thallus, in one or several layers>/

1. in a single layer in section/

2. in several layers in section/

3. irregularly distributed/

#61. The ventral surface <of the thallus, colour>/

1. green/

2. reddish brown/

3. purplish black/


#62. The plants <all forms, sexuality>/

1. dioecious/

2. bisexual/

#63. The plants <whether gametangia grouped>/

1. having the gametangia grouped into bracteate inflorescences/

2. with no grouping of gametangia into bracteate inflorescences/

#64. The <bisexual> plants <all forms, distribution of male and female components>/

1. autoecious <antheridia and archegonia on separate branches>/

2. paroecious <antheridia in bract axils proximal to the female inflorescence>/

3. synoecious <antheridia and archegonia mixed in the same inflorescence>/

#65. The antheridia <thalloid forms, whether protected by bracts (involucrate)>/

1. protected by bracts/

2. not protected by bracts/

#66. The gametangia and capsules <thalloid, location>/

1. borne externally <implicit>/

2. immersed in the thallus/

#67. The archegonia and sporophytes <thalloid, whether protected by bracts (involucrate)>/

1. protected by bracts/

2. not protected by bracts/

#68. The archegonia and sporophytes <thalloid, whether with a pseudoperianth>/

1. with a pseudoperianth <not homologous with leaves>/

2. without a pseudoperianth/

Pseudoperianth (of thalloid liverworts): a sheath or protective stucture arising from the thallus, protecting two or more archegonia and subsequently a sporophyte.

#69. The gametangia <male and/or female, whether borne on ‘receptacles’>/

1. borne on special <sessile or stalked> ‘receptacles’/

2. not borne on special ‘receptacles’ <implicit>/

#70. The female receptacles <thalloid, sessile or stalked>/

1. sessile/

2. stalked <on an archegoniophore>/

Receptacles: in Marchantiales, specialized structures borne on the thallys bearing sexual or asexual reproductive structures.

#71. The female receptacles <of thalloids, rays>/

1. cruciately 4-rayed/

2. stellately about 9–11 rayed/

3. not rayed/

#72. The male receptacles <of thalloids, sessile or stalked>/

1. sessile/

2. stalked <on an antheridiophore>/

#73. Male inflorescences <leafy forms, description>/

#74. Male bracts <of leafy forms, description>/

#75. Male bracts subtending <numbers of antheridia>/

1. a single antheridium/

2. 2 antheridia/

3. several antheridia/

#76. The antheridial stalks <structure>/


#77. The antheridia <whether mixed with paraphyses>/

1. mixed with paraphyses/

2. not mixed with paraphyses/

#78. Female inflorescences <leafy forms, description>/

#79. Perigynium <leafy plants, presence>/

1. present and well developed <a protective fleshy, tubular structure, developed at the stem apex after fertilization of the archegonium>/

2. absent or vestigial/

Perigynium: a fleshy, tubular structure, developed from the stem apex after fertilization of an archegonium and protecting the sporophyte. Often surmounted by a perianth (q.v.).

#80. Marsupia <presence, in leafy plants>/

1. present as downgrowths from stem apices, surrounding the developing sporophytes and carrying them into the substrate/

2. present but vestigial/

3. absent <implicit>/

Marsupium: a perigynial downgrowth from a stem apex bearing rhizoids, which comes to surround the developing sporophyte and carries it into the substrate.

#81. Female bracts <of leafy plants, associated with sporophytes>/

1. present <more or less differing from the leaves>/

2. absent/

#82. Female bracts <relative size>/

1. smaller than the (upper) leaves/

2. similar in size to the (upper) leaves/

3. larger than the (upper) leaves/

#83. Bracteole <of leafy plants, associated with sporophytes>/

1. present/

2. absent/

Bracteole (of leafy liverworts): in the present context, a single foliar structure associated with bracts subtending antheridia or archegonia, sometimes fused to one or both of them. Usually interpretable as a modified underleaf.

#84. Perianth <sporophytic, presence in leafy plants>/

1. present <a fusion subsequent to fertilization of two opposite leaves, or of these plus an underleaf>/

2. absent/

Perianth (of leafy liverworts): a tubular structure which initially encloses and serves to protect the developing sporophyte. It develops subsequent to fertilisation of an archegonium, by fusion of two leaves, or of two leaves plus an underleaf.

#85. Perianth <sporophytic, of leafy plant, description>/

#86. Perianth <whether distally plicate>/

1. distally plicate/

2. distally smooth, not plicate <implicit>/

#87. Perianth <whether beaked>/

1. distally beaked/

2. not beaked <implicit>/

#88. Calyptra <all forms, presence: very poorly recorded>/

1. present and well developed <usually developed from the venter of the archegonium and surrounding the developing capsule>/

2. absent <to become implicit?>/

Calyptra: a structure developed from the venter of an archegonium, which constitutes a thin protective covering of the immature sporophyte, occuring internally to perianth and perigynium, ultimately rupturing distally and remaining near the base of the seta.


#89. The sporophyte <of leafy and thalloid plants, general form>/

1. elevated by elongation of the seta, with no intercalary meristem/

2. elevated via an intercalary meristem/

3. comprising foot and capsule only/

#90. The capsule <of leafy and thalloid plants, shape>/

1. globose <more or less spherical>/

2. ovoid/

3. shortly cylindrical/

4. elongate-cylindrical/

#91. The capsule <with or without a columella>/

1. with a central, longitudinal columella <overarched by the sporogenous tissues>/

2. without a columella <implicit>/

#92. The capsule wall <of leafy and thalloid plants, number of layers>/


#93. The capsule <of leafy and thalloid plants, whether green>/

1. green/

2. not green/

#94. The capsule <of leafy and thalloid plants, manner of dehiscence>/

1. dehiscing via two valves/

2. dehiscing by four valves/

3. dehiscing irregularly/

4. indehiscent/

5. dehiscing via a lid/

6. dehiscing via a single longitudinal slit/

#95. The spores <of leafy and thalloid plants, -celled>/

1. unicellular when shed/

2. shed as tetrads/

#96. Elaters <in the capsule, presence: all forms>/

1. present/

2. absent/

Elaters: specialised, elongated cells with spiral thickening accompanying spores within capsules and derived via mitotic divisions of sporogenous tissue. Associated with spore dispersal.

Elaterophore: a structure within the capsule to which clusters of elaters remain attached.

#97. Elaters <uni- or multicellular>/

1. elongate-unicellular <implicit>/

2. (1-)2-several celled (‘pseudo-elaters’)/

#98. Elaters <all forms: thickening, mono- or bispiral>/

1. unispirally thickened/

2. bispirally thickened/

3. thickend via 3–4 spirals/

4. with annular thickenings/

#99. Elaters <all forms: free or persistent>/

1. free <deciduous>/

2. persistent on elaterophores/

3. remaining attached to the inner walls of the dehiscent capsule valves/

#100. The elaterophores <when present, basal or apical: all forms>/

1. basal/

2. apical/


#101. <Habitat water requirement>/

1. aquatic/

2. in wet places <including helophytic>/

3. mesophytic/

4. xerophytic/

#102. Occurring in <pH preferences>/

1. basic habitats <including calcicoles>/

2. neutral pH conditions/

3. acid conditions <including calcifuges>/

#103. <Whether nitrophilous>/

1. nitrophilous/

2. not nitrophilous /

#104. <Whether saxicolous:> /

1. saxicolous/

2. not saxicolous/

#105. <Whether montane:> /

1. montane/

2. not montane/

#106. <Habitats>/

British representation

#107. <Number of species in Britain and Ireland>/

species <in this region>/

#108. <General distribution>/

1. England/

2. Wales/

3. Scotland/

4. Ireland/


#109. Class/Division <cf. Smith (1990)>/

1. Hepaticae <cf. Marchantiophyta, Forrest et al., (2006)>/

2. Anthocerotae <= Anthocerophyta>/

#110. Subclass/Class <cf. Smith, 1990>/

1. Jungermanniidae <cf. Jungermanniopsida, Forrest et al., (2006)>/

2. Marchantiidae <cf. Marchantiopsida, Forrest et al., (2006)>/

#111. Order <cf. Smith (1990), Forrest et al. (2006)>/

1. Calobryales <syn. Haplomitriales>/

2. Jungermanniales/

3. Metzgeriales/

4. Sphaerocarpales/

5. Marchantiales/

6. Anthocerotales/

#112. Family <cf. Smith (1990)>/

1. Haplomitriaceae/

2. Lepicoleaceae/

3. Herbertiaceae/

4. Pseudolepicoleaceae/

5. Trichocoleceae/

6. Lepidoziaceae/

7. Calypogeiaceae/

8. Adelanthaceae/

9. Cephaloziaceae/

10. Cephaloziellaceae/

11. Antheliaceae/

12. Lophoziaceae/

13. Jungermanniaceae/

14. Gymnomitriaceae/

15. Scapaniaceae/

16. Geocalycaceae/

17. Plagiochilaceae/

18. Arnelliaceae/

19. Acrobolbaceae/

20. Pleuroziaceae/

21. Radulaceae/

22. Ptilidiaceae/

23. Porellaceae/

24. Frullaniaceae/

25. Jubulaceae/

26. Lejeuneaceae/

27. Codoniaceae/

28. Pelliaceae/

29. Pallaviciniaceae/

30. Blasiaceae/

31. Aneuraceae/

32. Metzgeriaceae/

33. Sphaerocarpaceae/

34. Targoniaceae/

35. Lunulariaceae/

36. Weisnerellaceae/

37. Conocephalaceae/

38. Aytoniaceae/

39. Marchantiaceae/

40. Ricciaceae/

41. Anthocerotaceae/


#113. Haploid chromosome number, n =/


#114. <Comments:>/

To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2005 onwards. The liverwort genera (Bryophyta: Hepaticae and Anthocerotae) of Britain and Ireland. Version: 24th February 2016.’.