Notes on Davalliaceae II. A revision of the genus Davallia

64 Pages·1994·8.5 MB·English

by  Nooteboom, H P

BLUMEA 39 (1994) 151-214
Notes on Davalliaceae II.
A revision of the genus Davallia
H.P.Nooteboom
Rijksherbarium/HortusBotanicus,P.O.Box9514,2300 RALeiden,The Netherlands
Summary
Thisrevision ofDavallia starts with achapterabout themorphologyofthegenus. InDavallia two
sections are recognized, sectionDavallia andthe newsection Scyphularia. The species formerly
belongingtoAraiostegia,Humata and/orPachypleuriaare incorporatedinDavallia. Thirty-four
species aredescribed,with onenew,Davallia rouffaeriensis, andfivenewcombinations orstatesare
made. Keys tothe genera(ofthe familyDavalliaceae)and the species (ofDavallia)are given.An
indexto alltreated species(andtheir synonyms) isgiven.
Morphology ofDavallia
Scales
The scales can be peltate or basally attached witha cordate, overlapping base
(sometimes calledpseudo-peltate). Becausethebase is verythinand overlapping this
conditioniseasily overlooked.
Although someauthorsregardbasifixedscales as importantforrecognizing genera
(Araiostegia was recognized almostsolelyonthischaracter), I cameto theconclusion
that the character, probably primitive, occurs almost atrandom withinthefamily.
Sometimesspecies thatare very similarto eachother,andprobably closely related,
differinthischaracter,e.g.,Davalliaembolostegia andD. denticulatavar. elata.Ina
fewcollections, maybehybrids, thisis theonly differenceseparating them!
Thescalesarebasifixedwithgready overlapping cordatebaseinthefollowing spe-
cies:Davalliaclarkei, D. divaricata, D. embolostegia, D. hymenophylloides, D.multi-
dentata, D.pulchra. (Davalliaclarkei, D. hymenophylloides, D.multidentataandD.
pulchra were formerly placed inAraiostegia, a genuswithsomeofthecharactersof
HumataorPachypleuria, such as muchdividedleavesandonly basally attachedin-
dusia,butwithbasifixedscales.)
Anotherdiagnostic characteris theshape ofthescales. InDavallodes(except D.
membranulosum, which IincludehereinDavallia), andin theformerly recognized
generaParasorus, Scyphularia, and Trogostolon they areacicular.Thismeans that,
from aroundbase, the scales abruptly taper into a very narrow, thread-like, distal
part thatis mostly curved outwardsabovethe appressed base. Kato (1985) has al-
ready explained thatacicularandnon-acicularscales arenot differentmorphologically
G The firstpaper in this series, 'Notes onDavalliaceae I',waspublished in Blumea 37 (1992)
127-185.
152 BLUMEA Vol. 39, No. 1/2, 1994
(nor, according to him,taxonomically). Iagreeto someextent withhim.Allspecies
ofDavallodespossess acicular(or nearly acicular) scalesbut they are notunique to
this genus.InDavalliathescales areflatandnearlyacicularinsomespecies (Davallia
denticulata, D. heterophylla, D. speciosa, andD.trichomanoides); thisconditionmay
occur together withnormal, graduallytapering scales as inD. denticulata. Acicular
scales occurinD.pentaphylla, D.triphylla (togethertheformergenusScyphularia), D.
seramensis, andD. undulata(Parasorus undulatus). Inmy opinion thesefourspecies
together formthesection Scyphularia. Davallia undulata differsfromallthe other
species ofthefamily inhaving a coenosorus. The only species ofDavalliaoutside
Scyphularia withacicularscales is D. falcinella (formerly Trogostolonfalcinella).
Anothertype ofscales, muchresembling thegradually taperingscales, occurs inD.
solida, and, together withnearly acicularscales,inD.trichomanoides.Thesescales
are evenly narrowedtowardstheapex abovethemuchbroaderbase.Thisformmay
beatransitionbetweenacicularandevenly narrowedscales.
Theoccurrence ofapical and marginal multicellularhairson the scales isoften
alsoconsideredanimportantcharacter,forinstanceinDavalliabrevipes, D. canarien-
sis, D. graeffei, D. leptocarpa, D.pectinata, D. repens, D. solida, D. triphylla, and
D. wagneriana. Thesespecies havepeltate scales incommon, but varyinotherchar-
acters suchasattachment ofindusiumandshapeofthescales.
Indusia
Theindusiacanbereniform,attached onlyatthenarrow,cordatebase,orattached
atabroadbase and hardlyor not atallatthesides, attachedatthebaseandonlypart
ofthesides, orattachedatthebaseandalong thesides (i.e.pouch-shaped. Itisclear
thatthedifferentconditionsare transitionaland difficulttouse forseparating genera.
TheformergenusHumatawas mainlycharacterizedby having only basally attached
indusia.Species withonly basallyattachedindusiaare Davalliaangustata, D.assami-
ca,D. brassii, D. clarkei, D. heterophylla, D. hymenophylloides, D. membranulosa,
D. multidentata, D.parvula, D.pectinata, D.pulchra, D. repens,D. rouffaeriensis,
D. sessilifolia, andD. sessilifolioides. Species withindusiaattachedatthebaseand
partofthesidesare Davallia corniculata, D.falcinella, D. grijfithiana, andD.spe-
ciosa. Species withpouch-shaped indusiaare Davalliabrevipes, D. canariensis, D.
corniculata, D. denticulata, D. divaricata, D.embolostegia, D. graeffei,D. leptocarpa,
D.pentaphylla, D. seramensis, D.solida, D. trichomanoides, D. triphylla, D. wag-
neriana, andDavallodeshirsutum.Itis noteworthy thatinDavalliacorniculataindu-
siamayhave thesideseitherpartially orcompletely attached.
Leafshape, hairiness and insertionofpinnules
Theincision oftheleaves is very diverse.Itvariesfrom anentireleaftoa decom-
pound leafwithuni-veinedultimatesegments.Inonespecies, Davalliarepens,both
undividedandcompound leavesoccur,infertileas wellasin sterileleaves.
Inthesmallgroupthatformsthesection Scyphularia undividedandimparipinnate
leaves occurtogether withacicularscales.
Compound leavesare generally deltoidandbroadesttowardsthebase.InDavallia
membranulosaandD. assamica, however, they areelongate andnotbroader,some-
timeseven narrowed, towardsthebase, acharacteralso occurringinDavallodes.
H.P. Nooteboom: Notes on Davalliaceae II 153
Thepinnules inDavallia are anadromous, i.e., the apical pinnule of atleast the
lowerpinnae isinsertednearerto therhachis than thebasalpinnule; thealternative
conditionis termedcatadromous(in Davallodesthepinnules are essentially catadro-
mous). InDavallia membranulosathey are more or less opposite (anadromous to
catadromous). Kato(1985) andI myself(Nooteboom, 1992)includedthisspecies in
Davallodes.Davallia membranulosaalsopossesses hairy leaves and axes,as doall
thespecies ofDavallodes.Butthischaracteroccurs inDavallia as well, viz. inDaval-
lia brevipes, D. (Araiostegia) multidentataandsometimesinD. heterophylla,D.pec-
tinata, andD.sessilifolia. Thescales ofDavalliamembranulosaare not acicularandI
thereforenowincludethisspecies inDavallia.Itis probably closestrelated toDaval-
liaassamica.
Sen,Sen & Holttum(1972) describeaerophores in two continuouspale lineson
thepetiole forDavalliaandHumataandnot forAraiostegia andDavallodes. As they
studiedonly afewspecies, andthis characterisobscure inherbariummaterial,Ire-
frainfromevaluating it. Kramer(1990) mentionstheseaerophores inthe description
ofthefamily.
Chromosomes
InDavalliax=40,inD. repensfrom SriLankatriploidy andapogamyisreported
(Manton & Sledge, 1954).
Spores (by GiselaRödl-Linder)
Thesporesare ellipsoidal withmonoleteaperture. The exosporeis colliculate-
verrucate, discretely verrucate, or fused verrucate to porous (the verrucae fusedto
theextentthatthesurfaceappearsporous). Alltransitionsoccurbetweenthe different
types,but generallythetypeisconstant foraspecies or groupofspecies.
IntheformergenusAraiostegia theperispore was describedas granulate, contrary
to thegenerally smoothperispore of Davallia.However,this characteroccurs only
inonespecies, Davallia (Araiostegia) clarkei. ThespeciesoftheformergenusAraio-
stegia vary intheornamentationoftheexosporein thesameway as thespecies of
Davallia. Porous spores,which arerare inDavallia, do not occur inAraiostegia.
Becauseclosely relatedspecies generally possess the samekindofspores,I doubt
whetherthe formergenusAraiostegia is monophyletic.
InDavalliaporousspores are foundinD. heterophylla together withatransition
offusedverrucate toporous, inD. seramensis, and inD. sessilifolia. InD. sessili-
folioides, whichis closelyrelatedtothelatter, atransitionoffusedverrucate toporous
spores is found. This typeisalso foundinD. wagneriana andD. corniculata, two
closely relatedspecies. Inafew collectionsofthevariableD.repens, heresuspected
to show introgression withthelattertwo species, thesame typealso is found. The
sizeofthesporesofD.repens variesbetween27 and46pm;thatofD. wagneriana
andD. corniculatais c. 27pm. As thereis oneapogamoustriploidreported, and the
sizevariesthroughout theareaofdistribution,Isupposethathybridizing resulting in
triploidy andpossibly polyploidy isthe cause oftheextreme high variability inD.
repens. Therest ofthecollectionsofD. repensstudiedpossess fused verrucate spores,
whichareoftentransienttothefused verrucate toporousspores. Moreover, this type
ofsporeis foundinD. heterophylla andD. undulata, species thatarequitedifferent.
154 BLUMEA Vol. 39,No. 1/2, 1994
Davalliaparvula, aspecies veryneartoD. repens,hasrugate-verrucatespores that
show alittlemorefusion oftheverrucae but closely resemblesthesporesofD. re-
pens; they fallwithinthevariabilityofD. repensin sizeandornamentation.This type
isalso foundinthedistinctD.pectinata. Many species possess colliculate-verrucate
spores, whichare ratherconstant fora species although transitions maybe found
withinone collectionwithdiscreteverrucate and discretetofusedverrucate. Inthis
large groupthereis no correlationwithother characters.Davallia canariensisdiffers
from allotherspecies inits distinctly tuberculateverrucae.
KEY TO THEGENERA OF THEFAMILYDAVALLIACEAE
la. Laminacompound. Pinnulesofatleastthelarger pinnae catadromous. Rhizome
scalesacicularor nearly acicular Davallodes
b. Laminafromsimple or imparipinate tocompound. Incompound leavespinnules
ofatleastthelarger pinnae anadromous. Rhizomescales acicularornot. Inone
species (Davalliamembranulosa) thepinnules arecatadromousbuttherhizome
scales evenly narrowedtotheapex 2
2a. Laminacompound. Scales basifixedalong broad base, rootsborne on allsides
ofrhizome, sori terminalattheveinendings Leucostegia
b. Laminacompound or not. Scalespeltate, or basifixed withcordatebase and
muchoverlapping lobes, roots restrictedtotheventralsideof lateralbuds,sori
facing midveinsat theforking pointofveins, or facing midveinsatthebending
pointofa vein 3
3a. Laminacompound. Soriexindusiate, extraaxillary lateralbudsintermediatebe-
tween two succeeding phyllopodia Gymnogrammitis
b. Laminacompound ornot. Soriindusiate, extraaxillary lateralbudslateraltothe
phyllopodia, or lowerlateralandslightly anterior Davallia
Conclusion
Fromthe argumentsused aboveIconcludethat thefamilyDavalliaceae counts
only fourgenera,Davallia,Davallodes, Leucostegia, and Gymnogrammitis.
Itis difficultto divideDavalliaintosections. Thereare noclearly definablegroups
except forsection Scyphularia, newlydefinedin thispaperwithDavalliapentaphylla,
D. seramensis, D. triphylla, andD.undulata(the numbers31-34).
Inalaterpaperthe generic delimitationwillbe discussed.
ACKNOWLEDGEMENTS
Iamindebted totheOrganizationNWO(NetherlandsOrganizationforScientific Research) forpro-
viding agranttovisit the herbaria ofTokyoBotanic Gardens(TI), Japanand Beijing (PE),China,
the Minister ofScienceandEducation,andthe Coordination Commission for Scientificand Educa-
tional Contacts with ChinaoftheRoyalDutch AcademyofSciences forprovidingagranttovisit
the herbaria ofIBSC and SYS in Guangzhouand KUNin Kunming,China,andtodo fieldwork in
Yunnan andHainan,China. Ialso wishtothankthe directors and/orcurators ofBM,IBSC,K,KUN,
P, PE, SING,SYS and TI forlettingme study the collections in their herbarium and ofA, BO,
KYO, and PNH forsendingonloan the collections needed for thisrevision. Ms. B.J.vanHeuven
made the SEMphotographsand Mr.J.H.vanOsmounted thephotographsandmade the drawings
ofmaps andotherplates,forwhich Iamvery thankful
H.P. Nooteboom: Notes on Davalliaceae II 155
Note — An identification list ofall collections is available from the Rijksherbarium atLeiden.
The descriptionsin thispaper are madewith the computerprogramme DELTA, and thekeys with
KCONI. A file to be used with ONLIN6 for on-line identification ofspecimens canbe obtained
fromthe author. With therequesta3.5"floppydiskshould besent.
LITERATURE
Ching, R.C. 1959.Davalliaceae. Fl. Reipubl.Popul. Sin. 2: 280-319, 374-378.
Copeland, E.B. 1908.New orinteresting Philippineferns III.Philipp.J. Sci. 3C: 31-39.
Copeland,E.B. 1927.Davallodes andrelated genera.Philipp. J.Sci. 34:239-257.
Holttum,R.E. 1972.The genus Davallodes. KewBull. 27:245-249.
Kato,M. 1985.Asystematic study ofthegenera ofthefern familyDavalliaceae. J.Fac. Sc. Univ.
Tokyo, sect. 3 Bot., 13:553-573.
Kato,M. 1989.Taxonomicstudies ofPteridophytes ofAmbonand Seram (Moluccas)collectedby
Indonesian-JapaneseBotanical ExpeditionsII.Davalliaceae andOleandraceae. J.Fac.Sc.Univ.
Tokyo, sect. 3 Bot., 14:226.
Kato, M. et al. 1992. Cytotaxonomic study offerns ofYunnan, Southwestern China. Bot.Mag
Tokyo 105: 105-124.
Kramer,K.U. 1990.Davalliaceae. In:K. Kubitzki (ed.), TheFamilies and Genera ofVascularPlants:
74-80.
Manton,I.,& W.A.Sledge. 1954.Observations onthecytology and taxonomyofthepteridophyte
flora ofCeylon. Philos. Trans.Roy. Soc.London,ser.B, 238: 127-185.
Nooteboom,H.P. 1992.Notes onDavalliaceae I.The generaAraiostegia,Davallodes,Leucostegia,
and Gymnogrammitis.Blumea 37: 165-187.
Sen,T.,U. Sen & R.E.Holttum. 1972.Morphology and anatomyofthe genera Davallia,Araio-
stegiaand Davallodes,with adiscussion ontheiraffinities.Kew Bull. 27: 217-243.
Tagawa,M„& K.Iwatsuki. 1970.Newor interestingferns fromThailand 6. ActaPhytotax.Geobot.
24: 175-181.
Tryon,A.F., & B.Lugardon. 1991.SporesofthePteridophyta.Surface, wall structure, and diver-
sitybasedon electronmicroscopestudies. SpringerVerlag,NewYorketc.
DAVALLIA
Davallia J.Sm.,M6m.Accad. Sci. Turin 5 (1793)414; Bedd.,Handb. Ferns Brit.India (1883)58;
Copel.,Philipp. J. Sci. 34 (1927)253; Tard.-Blot& C.Chr., Fl. Indo-Chine 7 (1939) 103;
Copel., Philipp. J. Sci. 73 (1940) 355; Gen. Fil. (1947)87; Fern Fl. Philipp. (1958) 170;
Ching, Fl. Reip. Pop. Sin. 2(1959)297; Holttum,Revis. Fl. Malaya2, sec. ed. (1966) 354;
DeVol & Yang,Fl.Taiwan 1 (1975)271; Brownlie, Pterid.Fl. Fiji (1977) 162.—Davallia
sect. Davallia Kato, J.Fac. Sci. Univ. Tokyo, sect. 3 Bot., 13 (1985) 566. —Type species:
Davallia canariensis (L.)Sm.
WibeliaBernh. (nonF6e, 1852),J.Bot.(Schrader)1801(1)(1801)122,t. 1, f.2.—Davallia sect.
Wibelia Kato,J.Fac. Sci. Univ. Tokyo, sect. 3 Bot., 13 (1985)566. —Typespecies: Wibelia
elataBernh.
Humata Cav., Descr. PI.(1802)272;Bedd.,Handb. Ferns Brit.India(1883) 46; Copel.,Philipp.
J.Sci. 34 (1927)253; Tard.-Blot & C.Chr., Fl.Indo-Chine 7 (1939) 108;Copel., Gen. Fil.
(1947)88; Holttum,Revis. Fl.Malaya2, sec. ed. (1955)364; Copel.,Fern Fl.Philipp. (1958)
175;Ching, Gen. Fil. (1959) 306; Tagawa,Col. Illustr. Jap. Pterid. (1959)67;Brownlie,Fl.
Nouv. Cal<5d. 3, Pterid. (1969)148;DeVol & Yang,Fl.Taiwan 1 (1975)274; Brownlie,Pterid.
Fl.Fiji (1977)158;Basu & Giri,J.Econ. Tax.Bot. 15(1991) 109. — Typespecies: Humata
ophioglossaCav.
Pachypleuria K.Presl,Tent.Pterid. (1836) 128;Epim. Bot.(1851)98; Kato,J. Fac. Sci. Univ.
Tokyo,sect. 3Bot., 13(1985)567. —Typespecies:Pachypleurispedata(Sm.)K.Presl.
156 BLUMEA Vol. 39, No. 1/2, 1994
StenolobusK.Presl, Tent.Pterid. (1836)129,t.4,f. 30.—Typespecies: Davallia solida (Forst.)
Sw.
ParestiaK.Presl,Epim.Bot.(1851)99.—Typespecies:Parestia elegansK.Presl.
Pteroneuron F6e,M6m.Foug.5,Gen. Filic. (1852)320,t.25B,f. 1.— Typespecies: Pteroneuron
parallelumFte.
Scyphularia F6e, M6m.Foug. 5, Gen.Filic. (1852) 324, t. 26B, f.1; Copel., Philipp. J.Sci. 34
(1927)254; Ibid. 73 (1940)356; Gen. Fil. (1947)88; Brownlie, Pterid.Fl.Fiji (1977) 166;
Kato,J.Fac. Sci. Univ.Tokyo, sect. 3Bot., 13(1985)567.—Typespecies: Scyphulariapenta-
phylla(Blume)F6e.
Parasorus Alderw.,Bull. Jard. Bot.BuitenzorgHI,4(1922)317,1.14;Copel.,Gen.Fil. (1947)89;
Kato,J.Fac. Sci. Univ. Tokyo,sect. 3Bot.,13(1985)568. —Typespecies: Parasorus undula-
tus Alderw.
AraiostegiaCopel., Philipp. J. Sci. 34 (1927)240, t. 1,2; Univ. Calif.Publ. Bot. 12(1931) 397,
t.53a;Gen.Fil. (1947)85;Holttum,Revis. Fl.Malaya2,sec. ed.(1955) 364;Copel.,FernFl.
Philipp. (1958) 166;Ching, Fl.Reip.Pop. Sin. 2(1959)285; Kato,J. Fac. Sci. Univ. Tokyo,
sect. 3 Bot., 13(1985)564. — Typespecies: Araiostegiahymenophylloides(Blume)Copel.
Trogostolon Copel., Philipp. J. Sci. 34 (1927)251, t.4; Gen. Fil. (1947)87; Fern Fl.Philipp.
(1958) 170;Ching,Fl. Reip. Pop. Sin. 2(1959)283; Kato,J. Fac. Sci. Univ. Tokyo, sect. 3
Bot.,13 (1985)568.—Typespecies: Trogostolonfalcinellus(K.Presl)Copel.
ParadavallodesChing,ActaPhytotax. Sin. 11(1966)18.—Typespecies:Paradavallodes multiden-
tata(Hook.)Ching.
Davallia sect. CordisquamaKato,J.Fac. Sci. Univ. Tokyo, sect. 3 Bot., 13(1985)566. —Type
species:DavalliadivaricataBlume.
Rootsrestrictedto theventral sideoflateralbuds.Scalesofrhizomepeltate orbasi-
fixedwithcordatebaseand greatly overlapping lobes, variously shaped: distinctly
acicular, or flatand nearly acicular, narrowedevenly towardstheapex, or narrowed
abruptly fromabroadbase,orbroad, ovate to oblong-subdeltoid withroundto acute
apex.Petiolesusually well developed, intwo ranks on thedorsalside oftherhizome;
adaxialfacesulcate, thegrooveusually raisedinthemiddle; smallspecies sometimes
withsubsessileleaves; petiole occasionaly persistently scaly. Laminasimple,impari-
pinnate, pinnate +pinnatifid, bipinnate +bipinnatifid, or tripinnate +tripinnatifid; if
compound deltoidand broadesttowards base orrarelyelongate, glabrous orrarely
bearing multicellular hairs, anadromousor rarely isodromousor catadromousand
thenthescales evenlynarrowedtowardstheapex;laminadimorphic ormonomorphic,
in dimorphic species with reducedleaftissueand/ormore dissected. Veinendings
onsterilesegmentsreaching themargin or not.False veinspresentinseveral species.
Rhachis winged andthereforeseemingly grooved adaxially butconvex betweenthe
wings. In thedrystate(re herbariumspecimens) itis difficultto seewhethertherhachis
itselfisgrooved or flat.Sori typically separatebutinD. undulataconnateand elon-
gate alongleafmargins; sorinearthemargin, facing midveinsattheforking point of
veinsor atthebending pointofa vein.
Distribution- FromIndiathrough continentalSEAsiatoChina, Korea,andJapan;
Malesia; thePacific toSamoaandNewZealand;NE Australia;theislandsintheIn-
dianOcean; Africa;onespecies inNW Africa,theCanary Islands, andSWEurope.
Maps 1-4.
Eightspecies arerestrictedtoa very smallarea: DavalliaassamicatoAssamand
neighbouring areas, D. brassiitoasmallareaaroundtheborderofWestNewGuinea
and Papua NewGuinea, D. leptocarpa to Aneityum in theNewHebrides,D. rouf-
faeriensis toaveryrestrictedarea neartheRouffaerRiverinWNewGuinea, D. ses-
H.P. Nooteboom: Notes on Davalliaceae II 157
Map 1— 1.Davallia angustataWall, ex Hook. &Grev.— 2.D. assamica (Bedd.)Bakerin Hook.
& Baker.— 3.D. brassii (Copel.)Noot. — 4.D. brevipesCopel. — 5. D. canariensis (L.) J.Sm. —
6. D. clarkei Baker. — 7.D. corniculata Moore. — 8a.D. denticulata(Burm.f.)Mett.ex Kuhn var.
denticulata—.8b.D. denticulatavar. elata (Forst.)Mett.exKuhn.— 9. D. divaricata Blume var.
divaricata.—10.D.embolostegiaCopel. — 11.D.falcinella(J.Sm.)K.Presl.
Map2 — 12.DavalliagraeffeiLuerssen. — 13. D. griffithianaHook. — 14.D. heterophyllaJ.Sm.
—15.D. hymenophylloides(Blume)Kuhn. — 16.D. leptocarpaMett.— 17.D. membranulosaWall.
ex Hook. — 18.D. multidentataHook. — 19.D.parvulaWall. exHook.& Grev.— 20.D. pectinata
J.Sm.— 21.D.pulchraD.Don. —22.D. repens (L.f.)Kuhn. — 23.D. rouffaeriensisNoot.
158 BLUMEA —Vol. 39, No. 1/2, 1994
Map3 —24.Davallia sessilifolia Blume. — 25.D. sessilifolioides Kato.—26a. D. solida (Forst.)
Sw. var. solida.—26b. D. solida var.pyxidata (Cav.)Noot. —26c. D. solidavar.fejeensis(Hook.)
Noot. —27.D. speciosa Mett.in Kuhn. — 28.D. tasmaniField. — 29. D. trichomanoides Blume
var.trichomanoides. — 30.D. wagnerianaCopel.(distribution areanot givenonthe map).—31.D.
pentaphyllaBlume.— 32.D. seramensisKato.—33.D. triphyllaHook. —34.D. undulata(Alderw.)
Noot.
Map4—Number ofspecies (abovethe hyphen)andnumber ofendemicspecies (belowthehyphen)
for each area.
H.P.Nooteboom: Notes on Davalliaceae II 159
silifolioides toCJeram (Moluccas), D.speciosa toMoulmeininBurma,D. tasmanito
ThreeKings Island,northofNew Zealand, andD.undulatatoHalmaheiraandTer-
natc (Moluccas).
Twospecies haveavery widedistribution,D. denticulatafromtropical WestAfrica
totheSociety IslandsinthePacific andD.repensfrom tropicalWestAfricatoSamoa.
The latterspecies is found as farnorthas Japan and as farsouth as the Kerguelen.
(The large variability is discussed underthisspecies. Whereasin theouterrangesof
its distributionthe species isratherconstant,itis highly variableintheinnerregions
whereitcomes intocontactwith otherspecies ofthegenus.)
Themajorityofthespecies havea moderately large areaofdistributioninSEAsia,
nineofthem extending farinto thePacific:D. brevipes, D. denticulata, D. embolo-
stegia, D.falcinella, D. heterophylla, D.pectinata, D.pentaphylla, D. sessilifolia, D.
solida; andD.leptocarpa andD. graeffeirestrictedto thePacific.
The distributionofD. canariensis, in northernAfricaand southwesternEurope,
liesoutside the areaof the otherspecies of the genus,just as the distributionof
D. tasmani attheotherside of theglobe. Nevertheless, bothspecies are sosimilar
thattheycouldbevarieties (Maps 1:5and3:28,respectively).
Therecentcentre ofdistributionofthegenus(andofthefamily)is clearlyMalesia
with 23 ofthe total34 species and 9 endemic species. Malesiaand thePacific to-
gether possess 16endemic species. Sumatra contains 16 species, Borneo 14, the
Philippines 13, the Moluccas 15, New Guinea 14, butthe Pacific also has a large
numberofspecies, viz. 14, of which 3 (one in New Zealand) are endemic. The
species endemic to Asia north ofthe Isthmus ofKra in SThailandnumberonly 7
(Map 4).
Thedistributionofsomanytaxafarinto thePacificmaybeaccountedforby the
factthatthe adverse tradeand monsoonwinds usually do not blow duringsporula-
tion. Atthattimethewinds blowtowardsthePacific, atleastinthePhilippines. Da-
valliacanadensis mightbearelictfrom theEocene. For thedistributionofD. tas-
manianexplanation is difficulttofind.
KEY TO THE SPECIES OF DAVALLIA
1a. Rhizomescales basifixedwithcordatebaseandmuchoverlapping lobes 2
...
b. Rhizomescales peltate 8
2a. Indusiumpouch-shaped, veins insterileultimatelobespinnate, veinendings on
sterilesegmentsreaching themargin 3
b. Indusiumreniformorsemicircular, attachedatthenarrow, cordatebase only, or
attachedatthebroadbase andhardly or not atthesides, veinsinsterileultimate
lobesfrequently simple or forked, veinendings onsterilesegmentsnot reaching
the margin 5
3a. Indusium upper margin elongated, free, separated from or even with lamina
margin orprotruding beyond laminamargin, indusiumlonger thanwide
10. D. embolostegia
b. Indusium uppermargin not elongated, truncate or slightly rounded, separated
fromor evenwithlaminamargin,indusiumwiderthanlong oraboutas wide as
long 4
160 BLUMEA Vol. 39, No. 1/2, 1994
4a. Laminastrongly dimorphous, sori frequently single ona segment, indusium
semicircular, widerthan long 9b. D. divaricatavar. dimorpha
b. Laminanot or slightlydimorphous, soriborneseveralona segment,indusium
oblong, about as wide as long 9a. D. divaricatavar. divaricata
5a. Pinnaesessile, scales not or seldomcurling backward 6. D. clarkei
b. Pinnaepetiolate, longest petiolules 2.5-30mmlong, scales curling backward
orappressed to rhizome 6
6a. Leafrhachises hairy 18. D.multidentata
b. Leafrhachises glabrous 7
7a. Rhizomescales appressed torhizome, broad, ovateto oblong-subdeltoid with
round to acuteapex, usually crisped, margins recurved .... 21.D. pulchra
b. Rhizomescalesoftencurlingbackward, narrowedevenly towardsthe apex
15. D. hymenophylloides
8a. Laminaimparipinnate, leafletsnarrow, muchlonger thanbroad,entireor nearly
so, occasionally lobed at thebase or once branched, or simple, one entire to
pinnatilobed leaf 9
b. Laminacompound or pinnate towards base, or simple, onepectinate or pinna-
tifidleaf, orthreefoliate, theleafletsmore orless divided 14
9a. Sori connate,elongate along leafmargins. Laminasimple 34. D.undulata
.
b. Soriseparate,laminasimple or imparipinnate 10
10a. Laminasimple, strongly dimorphous, indusiumwiderthanlong
14. D. heterophylla
b. Laminasimple or imparipinnate, not or slightly dimorphous, indusiumlonger
thanwide oraboutas wideaslong 11
11a. Rhizome not whitewaxy, rhizome scales bearing multiseptate hairs at least
whenyoung,indusiumlongerthanwide, 1.5-2.5 mmlong 12
b. Rhizomewhitewaxyunder thescales, scales not bearing multiseptate hairs, in-
dusiumaboutas wide as long,0.5-1 mm long 13
12a. Rhizomescales not or seldomcurling backward or appressed torhizome, 5 mm
long, marginofsterile leavesrecurved orrevolute 33.D. triphylla
b. Rhizome scales often curling backward, 6-10 mm long, margin ofsterile
leavesflator nearly so 31. D.pentaphylla
13a. Indusiumalsoattachedalong thesides, pouch-shaped, oblong, rhizome scales
with pale border quickly diminishing or disappearing towards theapex, dis-
tinctlyacicular, oftencurling backward,3-5mmlong, leavessimple
32. D. seramensis
b. Indusiumattachedatthebroadbaseand hardly or not atthesides, semicircular,
scales withoutpale border, narrowedevenly towardsthe apex,not or seldom
curling backward, 6-8 mm long 1. D. angustata
14a. Rhizomenotwhitewaxy 15
b. Rhizomewhitewaxyunderthescales 28
15a. Laminaelongate, oftennarrowingtowardsbase 16
b. Laminadeltoidandbroadesttowardsbase 18
16a. Laminabipinnate, bearing multicellularhairs,rhizomescales withpale border
frombase to apex 17. D. membranulosa