Key to the moss genera of North America north of Mexico

29 Pages·1992·15.5 MB·English

by  D H Vitt

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Contr.Univ.Mich.Herb. 18:43-71.1992.
KEYTOTHEMOSSGENERAOFNORTHAMERICA
NORTHOFMEXICO
DaleH.Vitt
DepartmentofBotany
UniversityofAlberta
Edmonton,AlbertaT6G2E9,Canada
WilliamR. Buck
NewYorkBotanicalGarden
Bronx,NY 10458-5126,U.S.A.
Traditionally,mosseshavebeenconsideredbymanytopresentseveredifficul-
ties in identification of both species and genera. However, often if the genus is
known, species identification follows with much less difficulty. Moreover, most
regionalmossfloraspresentkeystospeciesbeginningatcitherthefamilyorgenus
rank.WepresenthereakeytothegeneraofmossesfoundinNorthAmerica,north
of Mexico. The key is strictly dichotomous and attempts were made to use
gametophyticfeatureswheneverpossible.
Mosses (Class Bryopsida or Musci) are the largest group of plants in the
Bryophyta, and are the third largestclassofgreen land plants in North America
followingtheMonocotsandDicots.TherecentlypublishedlistsofNorthAmerican
mosses(Andersonetal. 1990[AndreaeidaeandBryidae];Anderson1990[Sphagni-
dae])tabulate 1320speciesin312genera.Tothese,weaddthegenusTakakiawith
twospecies(Murray1988;Smithetal. 1990).Withinthe313generaofmossesfound
inNorthAmerica, 15have15ormorespecies.Onlytwogenerahavemorethan50
species Spha—gnum with 72 —and Bryum with 66; five genera have 30 or species
{Ortho—trichum 37,Fissidens 36,GrimmiaandBrachytheciumeachwith34,and
Pohlia 30).OtherlargegeneraareTortula(29),Dicranum(27),Racomitrium(24),
Hypnum (21), Campylopus (18), Hygrohypnum (18), Encalypta (16), and Poly-
trichum (15). These 15generacontain476or36%oftheNorthAmericanspecies.
Historically,keystomosseshaveusedgrowthform(acrocarpyvs. pleurocarpy)
asamajordichotomy.Wehaveresistedtheuseofthischaracterwheneverpossible,
and instead placed more emphasison microscopicfeaturesofthe leaves; namely
thepresence,absenceandnumberofcostaefoundonleavesandontheornamenta-
tionofleafcells(papillosei^s. smooth).
Genericconceptsdependlargelyonpreviousmonographicworkcompletedin
particular families. Some North American families have had no recent generic
revision, while othershave newly revisedgenericconceptsin place. We have fol-
lowed the generic concepts presented in Anderson et al. (1990), including the
recognition of segregate genera in the Mniaceae, Amblystegiaceae, and Grim-
miaceae.ThesegenericconceptsdiffersomewhatfromthoseacceptedintheCana-
dian(Irelandetal. 1987)andEuropeanchecklists(Corleyetal. 1981).
ReprintsofthisarticlemaybepurchasedfromtheAmericanBryologicalandLichenologicalSociety.
vSendorderstoJerryA.Snider,Dept.ofBiologicalSciences,UniversityofCincinnati,Cincinnati,OH
45221-0006.U.S.A.
43
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44 CONTR.UNIVFRSIIYOFMICHIGANHERBARIUM VOLUMF1,S
FloristictreatmentsofNorthAmericanmossesareavailableformanyareasof
the continent, and date back to the 188()'s when Lesquereux and James (1S84)
publishedthe first treatmentofmossesofthecontinent. Stillavaluablesourceof
information and the only flora that treats the southwestern United States is
Grout's Moss Flora ofNorth Aincricd (Grout 1931-40). In more recent times
(since 1970)severalexcellentregionalflorashavebeenwrittenandformthe basis
ofourunderstandingofNort—hAmericanmosses. Includedarethefollowingmanu-
als: Eastern Nor—th America Crum and—Anderson (1981); the United States Pa-
cihc Northwest Lawton (1971); Utah Flow—ers (1973); northern Michigan
Crum (1973); Maritime Provinces of Canada Ireland (1982); the southeastern
GulfShore—Reese (198—4); the Interior Highlands—Redfearn (1983); andnorth-
western North America Vitt et id. (1988). Dehnition ofterms used in this key
followthosegiveninCrumandAnderson(1981)andinMagill(1990).
WehavethegreatprivilegetodedicatethiskeytoHowardCrum,ourteacher
andgoodfriend. Hispatienceandperseverenceinperformingtheunenviabletask
ofteachingboth ofusthe fundamentalsofscience and bryologyare remarkable.
Withouthim, neithero\uswouldhavebeenabletocompletethepresentwork.To
HowardCrumweuiveourheartfeltthanks.
I. Gametophytesseeminglyabsent(consistingonlyofprotonemata);sporo-
phytesofasymmetriccapsulesandpapillosesetae Buxbanniia
1. Gametophytespresent(withobviousleaves);sporophytesvarious .... 2
2. Leafcellsarrangedinanetw(Mkofnarrow,greencellsalternatingwith
largehyalinecells;branchesusuallyinclusters Sphagnum
2. Leafcells ofone kind (green), or ifoftwokinds, branches never in
clusters 3
3. Leaves attached in two rows on opposite sides ofthe stem (distichous)
4
3. Leaves attached all around the stem (foliate stems sometimes flattened
[complanate]) 7
4. Leavesappearingsplitatthebase,consistingoftwovaginantlaminae
whichclaspthestemandbaseoftheleafabove(equitant) .... Fissidcns
4. Leaveswithexpandedbases,notclaspingleafabove .'S
5. Leavesecostate;protonematalumincnis Schisiosicga
5. Leavesunlcostate;protonematanotluminous 6
6. Allleaveswitharough(papillose),linearsubula Distichiuni
6. Vegetative leaves with a smooth mucro; perichaetial leaves with a
smoothsubula Bryoxiphium
7. Leaves with lamellae or filaments on the adaxial (upper) surface ofthe
costa(excludingpropagula) 8
7. Leaves without lamellae orfllamentson the adaxial surface ofthe costa
(butprt)pagulasometimespresent) 23
8. Leaveswithfllamentsontheadaxialsurfaceofthecosta 9
8. Leaveswithlamellaeontheadaxialsurfaceofthecosta 10
9. Leafmarginsbroadlyinrolled(andmostlyobscuringthefllaments) .... Aloina
9. Leafmarginsreflexedtorevolute Crossidiiim
10. Leavesborderedwithelongatecells Alrichuni
10. Leaveswithoutelongate,marginalcells 11
11. Leavesciliateatupperpartofhyalinesheath Biirircnyiiopsis
11. Leaveseciliate 12
1992 VITT&BUCK:KEYTOMOSSGENERA 45
12. Upper leaf margins bistratose with paired, multicellular teeth; leaf
apiceswithslender,smooth,caducousawns;restrictedtothearctic
Lyellia
12. Upperleafmarginsunistratosewithsingleteethorentire;leafapices
muticousorwithserrateawns 13
13. Lamellae 2-4; leaves hyaline awned; plants small, less than 5 mm;
peristomenoneorrudimentaryandfragile Pterygoneurum
13. Lamellae4-50;leavesmostlynotawned;plantsmostlylarger;peristome
of32or64persistentteeth 14
14. Lamellaedistinctlywavy 15
14. Lamellaestraight 16
15. Upperleafmarginswithborderofhyaline,short-rhombiccells Psilopilum
15. Upperleafmarginsnotbordered OUgotrichum
16. Leaflaminaewithteethonabaxial(back)surface;calyptraenakedor
withafewhairs OUgotrichum
16. Leaflaminaesmoothatback;calyptraedenselyhairy 17
17. Plantswithcapsules 18
17. Plantswithoutcapsules 20
18. Capsules(2-)4(-6)-anglcd Polytrichum
18. Capsulescylindric 19
19. Capsuleswithoutstomates;luminaofapicalcellsoflamellaenotpyriform
Pogonatum
19. Capsuleswithstomates;luminaofapicalcellsoflamellaepyriform
Polytrichastrum
20. Apicalcellsoflamellaesmoothorwithfaintcuticularridges 21
20. Apicalcellsoflamellaepapillose 22
21. Plantssmall,lessthan6mmhigh;leavesneverawned Pogonatum
21. Plantslarger;leaveswithorwithoutawns Polytrichum
22. Apicalcellsoflamellaerounded,quadrateoroblate Pogonatum
22. Apicalcellselliptic-pyriform Polytrichastrum
23. Leavesdeeplylobcdwithlobeslinear-terete Takakia
23. Leavesneverlobed,flattened(althoughsometimesconcavewithmargins
inrolledorrecurved) 24
24. Leaves without a costa or costa short and double, double, or single
with2-3lateralspurs 25
24. Leaveswithasinglecostatoatleastmidleaf 114
25. Althoughappearingnone,costasingleandoccupyingentireleafarea,thus
leafappearingmultistratose 26
25. Costatrulynoneordouble;laminaalwaysunistratose 27
26. Leavesligulatc;greencells(chlorocysts)three-sidedinsection
Octoblephanim
26. Leaveslanceolate;greencellsfour-sidedinsection Leucohryum
27. Upperleafcellspapilloseorprorulose 28
27. Upperleafcellssmooth(rarelywithminutecuticularroughenings) ... 46
28. Leafapiceshyaline 29
28. Leafapicesconcolorous 30
29. Leafcells with a single, unbranched papilla (on each surface); capsules
exserted, ribbed; perichactial leaves entire; restricted to western North
America Pseudobraimia
29. Leafcellswith 1-2forkedpapillae(oneachsurface);capsulesimmersed,
smooth;perichactialleavesciliate;widespread Hedwigia
46 CONTR UNIVERSIIYOI MlCHKiAN[II-RBARIUM VOlIJMHIS
30. Lealcellspluripeipillosc 31
30. Leafcellsunipapilloseorpiorulose 33
31. Papillaearrangedin rowsovertheluniina;leal cellsmorethan5:\
Taxithcliitin
31. Papillaerandomlyarrangedoverkmiina;leafcellslessthan4:1 32
32. Leavesobtuse:stemscomplanate-foliate Erpoiliitni
32. Leavesshort-acuminate;stemssymmetricallyfoliate Ihauiiid
33. Plants 2-3-pinnatc, each year forming a flattened frond, the fronds ar-
rangedinastair-stepascendingpattern Hvloconiiutn
33. Plantssimpleor 1-pinnate,notformingascendingfronds 34
34. Leavesplicate 35
34. Leavesnotplicate 36
35. Costadouble andextendingtoabove midleaf; leavesspreadingtosquar-
rose R/iytldiadelphiis
35. Costashortanddouble;leavesfalcate-secund Cfcnidiuiii
36. Plantsreddish-bhick,occurringtightlvattachedlorocks Andreaea
36. Plantsgreenish,occurringonvarioussubstrates 37
37. Plantsminute,lessthan2mm,acrocarpous Ephenicnini
37. Plantslarge, morethan 1 cm,pleurt)carpous 38
38. Costastronganddouble,extendingtonearleafapex Callicoslclla
38. Costashortandtioublc.endingbelowmidleaf 39
3*^^ Alarcellsnumerous,oblatetorounded,stronglydifferentiatedandextend-
ingupthemargins;restrictedtoPacificNtMthwest Pteroi^oniufn
3^). Alar cells few, mostly quadrate, scarcely extending up the margins;
widespread 40
40. Cellsatmidleafmorethan5:1 41
40. Cellsatmidleaflessthan5:1 43
41. Apicalleafcellsmuchshorterthanthoseatmidleaf Taxiphxlhuu
41. Apical leafcellsscarcelydifferentiated 42
42. Leaxesslenderly acuminate; prorulose at both upperand lowerends
ofcells Chryso-hypnitni
42. Leavesacute;proruloseonlyat upperendsofcells .... Leptohynwiuuni
43. Stemandbranchleavesdifferentiated Hetcroclacliuin
43. Stemandbranchleavessimilar 44
44. Leavesbroadlyovate,concave,obtusetoobtuse-apiculate .... Myiirella
44. Leaveslanceolatetoovate-lanceolate,acutetoacuminate 45
45. Leavesacute,serrulateonlyabove;propagulaofteninleafaxils;northern
indistribution Fteri^ynandruni
45. Leaves acuminate, serrulate throughout; propagula absent; eastern U.S.
indistribution Sc/nvetschkcopsis
46. Leavesendinginahyalineawn 47
46. Leavesconcolorousatapex 48
47. Leafcells2:1 orless,oblate-hexagonalthroughout;eperistomate ... Erpodiuni
47. Leafcellsmorethan3:1, uppercellsshortlyrhomboidal,basalcellsquad-
rate;peristomate VenturieUa
48. Plants aquatic, occurringsubmerged at least partofthe year; leaves
keeledorflat Fontinalis
48. Plants sometimes in wet habitats but ne\er occurring submerged;
leavesvariousbutneverkeeled 49
49. Plantsacrocarpous,usuallylessthan4cm 50
49. Plantspicurocarpous,mostlylarger 53
1992 VITT&BUCK:KEYTOMOSSGENERA 47
50. Plantsoccurringonrock 51
50. Plantsoccurringonbaresoil 52
51 Plantsreddish-black;capsulesvalvate Andreaea
.
51. Plantsgreenish-brown;capsuleswithfourperistometeeth .... Tetrodontium
52. Protonemataabundant;capsulesovoid,apiculate;calyptraecampanu-
late-mitrate,deciduous Ephemerum
52. Protonematasparse;capsulesglobose;calyptraeverysmall,persistent
Micromitrium
53. Costasinglewithoneorsometimestwosupplementarycostaeoneachside
Antitrichia
53. Costadouble,orifsingleveryshortandwithoutsupplementarycostae
54
54. Costalonganddouble,extendingtoorbeyondmidleaf 55
54. Costashortanddouble,usuallyendingjustaboveleafbase 59
55. Stemswithnumerousparaphyllia 56
55. Stemslackingparaphyllia 57
56. Stemleavesplicate,decurrent Hylocomiastrum
56. Stemleavesnotplicateordecurrent Loeskeobryum
57. Leafcellsthin-walled,lax,abruptlyborderedbyelongatecells
Cyclodictyon
57. Leafcellsfirm-walled,notoronlygraduallybordered 58
58. Plants forming mats; leavesfalcate-secund at least at branch apices;
exostometeethstriate,furrowed Trachyxiphium
58. Plants tufted; leaves somewhat contorted when dry but not falcate;
exostometeethpapillose,notfurrowed Lepidopdum
59. Leavesobtuse;plantssmall,rare,restrictedtothemountainsofsoutheast-
ernUS 60
59. Leaves acute to acuminate, at least apiculate; plants mostly larger,
widespread 61
60. Leavesasymmetricwithabasallobe Homaliadelphus
60. Leavessymmetricwithoutlobe Bryocrumia
61. Leafcellslax,hexagonal 62
61. Leafcellsfirm-tothick-walled,roundedtolinear 63
62. Lateralanddorsalleavesdifferentiatedinareolation;stemspinnately
branched Vesicularia
62. Lateral and dorsal leaves with similar areolation; stems irregularly
branched Hookeria
63. Leavesslenderlylong-decurrent Plagiotheciiim
63. Leavesnotatalldecurrenttobroadlyauriculate 64
6644.. PPllaannttssslalregnedre;r,letahvreesadm-loirkee;thleaanve1smmmostlloynglessthan 1 mmlong .... 6657
65. Branchleavesmorethan0.5mmlong Homomallium
65. Branchleaveslessthan0.5mmlong 66
66. Costashortandsingle;leafcellsrounded-elliptic Fseudoleskeella
66. Costanoneorveryshortanddouble;leafcellsrhombic .... Platydictya
67. Leavesfalcate-secund 68
67. Leavesstraight 84
68. Upperleafcellsoblong-rhombic,ca.3:1 69
68. Leafcellsmoreorlesslinear,morethan6:1 70
69. Alarcellsnumerous,oblate,extendingupthemarginsinmanyrows
Leucodon
48 C^ONTR.UNIVERSITYOI MKIlICrANHERBARIUM VOLUME18
69. Alarcellsfew,obknig-qiiadratc,in 1-2ixnvsak)ngtheiiiserticin
Senuitophvlluni
70. Plants regularlyandcloselypinnate,feather-like; trcindsHat,erect\o
ascending,oblong-triangular Filliuni
70. Plantsirregularlypinnatetounbranchcd,notfcathcr-likc;stemspros-
tratetolooselyascending 71
71. Mature branches erect and producing abundant and conspicuous propa-
gulaintheirupperleafaxils Flatyi^yriiim
71. Branchesnotproducingpropagulainleafaxils 72
72. Branchescurved-secund when dry, erect when moist; alarcellssmall
andquadrate FylaisieUa
72. Brancheslittlealteredwhendry;alarcellsvarious 73
73. Alarcellswhendifferentiatedquadrate,sometimesenlargedbutnotatall
inflated 74
73. Alarcellsquadratetooblong,inflated 79
74. Stemswithparaphyllia Rhytidiopsis
74. Stemswithoutparaphyllia 75
15. Plants very large (stem leaves 3.5-5.0 mm), stems ascending to erect;
leavesplicate Rhylidiadelphus
75. Plantssmaller(stem leaveslessthan 3.5 mm),stemsprt)strateloascend-
ing;leavesvarious 76
76. Alarcellsnoneorveryfew;palepropagulaoftenclusteredinleafaxils
Isopterygiopsis
76. Alarcellsdistinctlydifferentiated;clusteredpropagulalacking
^ ^ 77
77. Plantst)ccurringonwetrcK^ksinmountainstreams Hygrohypniiin
11. Plantsinvarioushabitatsbutnotasabove 7(S
78. Costatoca. '/< the leaflength with the two forks not meetingat the
base;plantsofAlaskaandYukon GolUuua
78. Costamostlyshorter, theforks joiningat thebase;plantswidespread
Hypnwn
79. Plants occurring in calcaret)us fens or marl pt)ols, dark reddish-brown;
leavesobtuse Svorpid'nun
79. Plants occurring in other habitats, golden to green; leaves acute to
acuminate 80
80. Plantsoccurringonwetrocksinmountainstreams Hygrohypnum
80. Plantsinvarioushabitatsbutnotasabove 81
81. Alarcellsthick-walled,inflatedinseveralrows;leafmarginsstronglyserrate
Hetcrophylliuin
81. Alar cells inflated in l(-2) rows, ox if more, thin-walled; leaf margins
entiretoserrulate 82
82. Stems sinrounded by enlarged, thin-walled, hyaline cortical cells
(hyalodermis);alarcellsinlarge,suhdecurrentareas Hvpnuni
82. Stemssurroundedbysmall,thick-walled,concolorcuiscells;alarcells
in l(-2)rows 83
83. Plantsveryshiny; leaves0.8-1.4mm long, denselyserrulate above;cap-
sulesinclined,asymmetric Brothcrelhi
83. Plants slightly shiny; leaves0.5-1.1 mm long, distantly serrulate above;
capsuleerect,symmetric Pyliusiudelphd
84. Stemleavesabruptlycontractedtolongsetaceouspt)int 85
84. Stemleavesacute,acuminateorapiculate 86
1992 VITT&BUCK:KEYTOMOSSGENERA 49
85. Leafapiceshyaline;alarcellsscarcelydifferentiated Iwatsukiella
85. Leafapicesyellow;alarcellsinflatedandhyaline Wijkia
86. Leavessquarrose-recurvedwhendry,withchanneledapices 87
86. Leaveserecttospreading,orifsquarroseonlywhenmoist,theapices
mostlynotchanneled 88
87. Stem leaves greater than 2.5 mm long; alarcells oblong, somewhat in-
flated,intramarginal Rhytidiadelphus
87. Stem leaves less than 2.5 mm long; alar cells subquadrate, not at all
inflated,marginal Campyliiim
88. Plantsoccurringonwetrocksinmountainstreams;leavesovate,concave
Hygrohypnum
88. Plantsinotherhabitatsbutnotasabove;leavesvarious 89
89. Stemscomplanate-foliate 90
89. Stemssymmetricallyfoliate 96
90. Alarcellsnumerousandquadrate;capsuleserect Entodon
90. Alarcellsfew,variouslyshaped;capsulesusuallyinclined 91
9L Plantsoccurringonverticalsubstrates,treetrunksorrocks Neckera
91. Plantsoccurringonhorizontalsubstrates,rarelytheextremebasesoftrees
92
92. Leafmarginsserrulatethroughout 93
92. Leafmarginsentireorserrulateonlyinupperhalf 94
93. Apicalleafcellsshorterthanthoseatmidlcaf Taxiphyllum
93. Apicalleafcellsundifferentiated Herzoglella
94. Rhizoids arisingfrom leafaxils, papillose; leafmarginsmore or less
entire Isopterygiopsis
94. Rhizoidsarisingfrombelowleafinsertion,smooth;leafmarginsserru-
lateabove 95
95. Pseudoparaphyllia filamentous; annuli not differentiated; plants mostly
monoicous Isopterygium
95. Pseudoparaphylliaabsent;annulidifferentiated;plantsmostlydioicous
Pseudotaxiphyllum
96. Alarcellsinflated 97
96. Alarcellsrectangulartoquadrate,notinflated 101
97. Plantserect;stemswithhyalodermis;alarcellshyalineandinauricles
Calliergonella
97. Plants prostrate; stems without hyalodermis; alarcells yellowish, not in
auricles 98
98. Alarcells uniform, without an enlarged basal row; stem apices flat-
tened Callicladium
98. Alarcellswithanenlargedbasalrow;stemapicesnotflattened ... 99
99. Alarcellsroundedtotheinsertion;exostomcteethfurrowed .. Acroporium
99. Alarcellsnotroundedtoinsertion;exostometeethnotfurrowed 100
100. Exostome teeth striate; endostome with evident basal membrane
andsegments;easternNorthAmerica Sematophyllum
100. Exostometeethsmoothorfaintlypapillose;endostomefugaceous,
appearingabsent;restrictedtooakscrubincentralFlorida
Donnellla
101. Plantswith numerous (morethan50), quadratealarcells,extendingup
themarginsbymorethan12rows 102
101. Plantswithfewer(lessthan25),quadratetorectangularalarcells,extend-
ingupthemarginsinlessthan8rows 107
."^O CONTR UNIVHRSITYOl MICHICtANHERBARIUM VOLUMI- IS
102. Stemswithnumerousparaphyllia Alsia
102. Stemslackingparaphyllia 103
103. Leaveslessthan 0.8mm long; cellswith obscurecuticularroughenings;
westernmontane Leptoptehgynandrum
103. Leavesmorethan 1 mmlong;cellssmooth 104
104. Alarcellsextendingupthe marginsforlessthan '/(,the leaflength
105
104. AlarcellsextendingupthemarginsformorethanVytheleaflength
106
105. Leavesacuminate,somewhatdecurrent;endostomewithcilia;plantsre-
strictedtocoastalwesternNorthAmerica,('aliforniatoBritishColumbia
TriplerocUuliiun
105. Leavesmostlyobtusetoacute,rarelyacuminate,neverdecurrent;endo-
stome lackingcilia; plantswidespread but not in coastal western North
America Entodon
106. Secondarystemsfreelysubpinnatelybranched Forsstroetnia
106. Secondarystemssimpleorwithfewbranches Leucodon
107. Plantsepiphyticwitlicreepingprimarystemsanderectsecondarystems
\ 108
107. Plantsterrestrialorrarelyonbasesoftrees,primaryandsecondarystems
notdifferentiated 109
108. Secondarystemsunbranched; leavesspreadingwithsquarrosetips;
propagulacommon /aegcrina
108. Secondary stems irregularly branched; leaves erect; propagula ab-
sent Nt'oniacoiinid
109. Stemswithhyalodcrmis;leafmarginsserrulatetobase Herzogiclla
109. Stemswithouthyalodcrmis;leafmarginsentireorserrulateabove ... 110
110. Leavesplicate Orihoihecimu
110. Leavesnotplicate Ill
111. Leafapicesobtuse-iipiculate 112
111. Leafapicesacuminate 113
112. Plantsoccurringinfens;stemsgreen,sparselybranched
Pseudocalliergon
112. Plants widespread in acidic habitats of the boreal forest; stems
reddish-orange,pinnatelybranched Pleuroziuni
113. Leafcellsporosethroughout;pseudoparaphylliaabsentorfoliose;plants
inboreal,arcticandalpinehabitats Orihotheciuni
113. Leafcellsnotporoseexceptatinsertion;pseudoparaphylliafilamentous;
plantsofcoastaleasternNorthAmericainlandtotheMidwest
IsoplerygiuDi
114. Plantserect,dendroidorfrondosefrcmianonbranchedstipe ... 115
114. Plantsprostratetoerect,simpletopinnatelybranched 121
115. Leavesborderedbyelongatecells 116
115. Leavesnotbordered 117
116. Plants with two kinds ofleaves, the largerones with costa ending
well below apex, the smaller ones (amphigastria) with excurrent
^"osta Hypopicrygiuni
116. Plantswithleavesallofonekind,thecostasubpercurrent
Lcucolepis
117. Stemswithparaphylliaorhlamentous,paraphyllia-likestructures .... 118
1992 VITT&BUCK;KEYTOMOSSGENERA 51
117. Stemswithoutparaphyllia 120
118. Plantsepiphytic;stemspinnatelyfrondose,curledwhendry,spread-
ingwhenmoist Dendroalsia
118. Plants terrestrial (rarely on tree bases); stems dendroid, little al-
teredwhendry 119
119. Branchleaveslong-decurrent,thedecurrenciesofinflated,hyalinecells;
stemswithlamellae;stemleaveswithentiremargins Pleuroziopsis
119. Branchleavescordatetoauriculate,theauriclesnotinflated;stemswith
paraphyllia;stemleaveswithserratemargins Climacium
120. Apicalcellsofbranchleavesrhombic;costaofbranchleavesstrong,
nottaperingtowardapex Thamnohryum
120. Apicalcellsofbranchleaveslong-hexagonal;costaofbranchleaves
slender,taperingtowardapex Porotrichiim
121. Plants blackish, tightly attached to rocks in arctic and montane areas;
capsulesvalvate 122
121. Plantsgreenishtoblackish,onvarioussubstrates;capsulescleistocarpous
oroperculate,nevervalvate 123
122. Plants occurring on calcareous rocks; capsules not hygroscopic,
turbinate,obtuse-conic Andreaeobryum
111. Plantsoccurringonacidicrocks;capsuleshygroscopic,whenmoist
elliptic,taperingtoapoint Andreaeci
123. Leavesstronglysquarrose-recurvedwetordry;plantsoccurringin fens
Paludella
123. Leaveserecttosquarrose;plantsoccurringinvarioushabitats 124
124. Stemswithparaphyllia 125
124. Stemslackingparaphyllia 142
125. Stemscomplanate-foliate;stemleavesundulate Metaneckera
125. Stemssymmetricallyfoliate;leavesnotundulate 126
126. Alarcellsinflatedinwellmarkedgroups 127
126. Alarcellsmostlynotdifferentiated,ifso,notinflated 128
127. Stemleavesdeeplyplicate;paraphylliafilamentous,abundant
Paluslriella
127. Stemleavesnotplicate;paraphylliafoliose,sparsetoabundant
Cratoneiiron
128. Paraphylliawithshortcells, 1-3:1 129
128. Paraphylliawithelongatecells,morethan5:1 140
129. CellsofparaphyUiapapillose 130
129. Cellsofparaphylliasmooth 134
130. Leafcellsunipapillosc 131
130. Leafcellspluripapillose 132
131. Plantsonce-pinnate;leafcellspapilloseonbothsurfaces Abietinella
131. Plants2-3-pinnate;leafcellspapilloseonlyatback Thuidium
132. Plantslarge,dioicous;leafcellspapilloseonlyatback Thuidium
132. Plantssmall,autoicous;leafcellspapilloseonbothsurfaces .... 133
133. Plants once-pinnate; leaves not incurved when dry; leaf cells strongly
bulging;setaesmooth Rauiellci
133. Plants 1-2-pinnate; leaves incurved when dry; leaf cells flat; setae
smoothorpapillose Cyrto-hypnum
134. Papillae of leafcells large, either forked or elongate and curved;
leavesbroadlvovate Thelia
52 CONTR.IJNIVHRSITYOIMICHIC.ANHI-:RBARII:M VOLUME18
134. Papillae of leaf cells small, simple: leaves lanceolate t(^ ovate-
lanceolate 135
135. Costapellucid;leavesusuallywithhair-points CIdopodiuni
135. Costaopacjue; leaveslackinghair-points 13(")
136. Stemandbranchleavesdifferentiated HaplocUuUniii
13(i. Stemandbranchleavesimiform 137
137. Leafcellsisodiametricornearlyso, hexagonalioshort-rhombic 138
137. Leafcellselongate,oblong-rhomhictooblong-linear 13*-)
13(S. Capsules inclined, asymmetric; ext>stome teeth striate; plants
largelywestern Fseudoleskca
138. Capsules ereci:, symmetric; exostome teeth pale and papillose;
plantslargelyeastern Leskea
139. Capsuleserect,symmetric;endostomesegmentsnarrow, notkeeled
Lcscuracii
139. Capsulesinclined,asymmetric;endostomesegmentsbroader, keeled
Pseudoleskea
140. Leafmarginsentiretoserrulate flclodiuni
140. Leafmarginsstronglyserrateinupperhalf 141
141. Upperleafcellsshort.2-5:1;plantso(southeastern UnitedStates
Clinniciuni
141. Upperleafcellslinear,morethan8:1;plantswidespread
UylocoDuastruni
142. Plantswhitish;leavescomposedmostlyofctista,multistratose,with
smallgreencellsenclosedbetween2layerso{hyalinecellson both
surfaces 143
142. Plantsgreenish \.oblackish, rarelywhitish; leaves usuallywith con-
spicuous lamina, ifnotgreencellsand hyalinecellso{aboutequal
size with only a single layer of hyaline cells on either side of the
greencells 144
143. Greencellsinsection4-sided;plantsterrestrial Leucohryum
143. Greencellsinsection3-sided;plantsepiphytic Octohlepharum
144. Leafmarginsstronglyincurvedtoinvolute,atleastwhendry ... 145
144, I^eafmarginsplanetorecurved 149
145. Leafmarginsincurvedwetordry 146
145. Leafmarginsincurvedwhendry.planewhenmoist 148
146. Leafcellspapillose;costawithtwostereidbands 147
146. Leafcellssmooth;costawithonestereidband Indusiella
147. Capsulesexserted.operculate Weissia
147. Capsulesimmersedtoemergent,cleistocarpous Astomum
148. Costawithsinglestereidband;peristomepresent Neohyophila
148. Costawithtwostereidbands;peristomeabsent Hyophila
149. Plants minute, occurringon soil (orrarely rock), ephemeral, oftenwith
persistentprotonemata;capsulesimmersed 150
149. Plantsmostlylarger,occurringonvarioussubstrates, mostlynotephem-
eral,orifso,capsulesexserted 161
150. Capsulesoperculate 151
150. Capsulescleistocarpous 152
151. Exothecialcellscollenchymatous Aphanorrhegnia
151. Exothecialcellsnotthickenedatcorners Physconutrium
152. Sporesfewpercapsule,morethan 100/xmindiaiueter 153