Three new species of the genus Lasianthus (Rubiaceae) from Vietnam

7 Pages·2002·1.2 MB·English

by  Zhu, H

BLUMEA 47 (2002) 395-401
Threenewspecies of the genusLasianthus
(Rubiaceae) from Vietnam
H. Zhu & M.C. Roos
Nationaal Herbarium Nederland. UniversiteitLeiden branch,
P.O. Box9514,2300RALeiden,The Netherlands
Summary
Threenewspeciesofthe genusLasianthus(Rubiaceae)fromVietnamarerecognisedasL. elevati-
neurus, L. longissimus andL. oblongilobus.
Key words: Lasianthus, Rubiaceae,Vietnam.
Introduction
LasianthusJackis alarge genusinthefamily Rubiaceaewithmorethan180 species.
Itoccurs fromtropical Asia(morethan160species) andAustralia(only onespecies)
to tropicalAfrica(c. 20species) as wellas tropical America(3 species) andhas the
centre ofspecies diversity intropical Asia.Thespecies ofthegenusoccuralmostex-
clusively inprimary forests.Someofthemare dominantunderstory shrubsor treelets
oftropicalAsianrainforestandmanyofthemarerare plants.As Lasianthusis a'dif-
ficult'genus,fewtaxonomicstudieswereundertaken,althoughthereare afewregional
revisions.LasianthusfromVietnamwas initiallystudiedbyDrake(1895;asMephitidia
Reinw. ex Blume). Pitard(1924) treated RubiaceaeforFlora Indochina(including
Vietnam, LaosandCambodia)andparts ofSiam(Thailand).Herecorded37species
including 5 varieties.Whilechecking specimens onloanfromAAUforrevising Lasi-
anthus for Flora Malesiana, three species fromVietnamare recognised as new.All
threenewspecies areknownfromtype collectionsfromspecimens onloanfromAAU.
Lasianthus elevatineurusH. Zhu,spec. nov. —Fig. 1
Proximus L. lucido Blume,sedfoliismajoribusellipticis vel elliptico-lanceolatis,nervis
7-8 binis,stipularisoblongis veloblongi-lanceolatis,bracteislinearis differt.AL. loei-
ensis H. Zhuramulis foliissubtus sparse hirsutis vel subglabris,nervulis supra promi-
nentibus,bracteis numerosis longioribus,stipularis oblongissparse hirsutis,fructibus
glabrisdiffert.-—Typus: L.Averyanov etal. VH3045 (holoAAU),Vietnam,Lam Dong,
12°06'N, 108°39' E,2100-2200 malt., inbroad-leaved cloudforest,22 March 1997.
1) Permanent address: XishuangbannaTropical Botanical Garden, the Chinese Academy of
Sciences,Kunming650223,People'sRepublic ofChina.
396 BLUMEA Vol. 47, No. 2, 2002
Fig. 1.Lasianthus elevatineurus H. Zhu, showing holotypewith enlarged fruits (L.Averyanov
et al. VH 3045).
H.Zhu & M.C. Roos: Three new species ofLasianthus from Vietnam 397
Shrub, upto 2.5m high;branchletstereteor slightly compressed, sparselyhirsute, or
glabrescent. Stipules oblong to oblong-lanceolate, 4-5 mm long, sparsely hirsute.
Leaves elliptic-lanceolate, 8-10by 2-3.5cm,subcoriaceous,glabrous aboveexcept
sparsely hirsute midrib, glabrous or puberulous beneathexcept hirsute midriband
nerves, base acute, apex acuminate, aristate, arista 2-3 mm long, hirsute, margin
recurved, slightly undulate,midribprominent both surfaces, nerves prominent both
surfaces, 7or8 pairs, nervulesprominent both surfaces, parallel; petioles short, c.2
mmlong, hirsute. Flowersin axillary, sessile fascicles; bracts linear, 5-6mm long,
hirsute; calyx obconical,calyx tubec.2mmlong, subglabrous, calyx lobes5, linear,
c. 3 mm long, hirsute; corolla not seen; ovary 5- or 6-locular.Drupes globose, 3-4
mmdiam.,with5 or6obtuseridges, glabrous, crownedby calyx lobes;thepersistent
calyxlobeslineartolinear-lanceolate,3-4mmlong, sparsely hirsute;pyrenes5 or6,
smoothon theabaxialface, orbicularintransverse section.
Distribution— SouthVietnam,knownonly fromthetypelocality.
Habitat&Ecology — Inmontane cloudforest.Fruiting: March.
Note—Thisspecies isrelatedtoL. lucidusBlumeby having asimilarcalyx with
linearor linear-lanceolatelobeswhichare longer thanthetube.Itdiffers fromL. luci-
dusBlumeby having relatively big elliptic to elliptic-lanceolate leaves with7 or8
pairs ofnerves, oblong to oblong-lanceolate stipules (4-5 mmlong) andnumerous
linearbracts ((L. lucidusBlumehas relatively small ovate leaves with 3-6pairs of
nerves, smalltriangular stipules(1-2mmlong)andbractsabsent). Itisalsorelatedto
L.loeiensisH.ZhufromNEThailand,butthelatterdiffersinhaving densely tomentose
branchletsandlowerleafsurface,hairydrupes,obscure nervulesabove,linear-subulate
and densely tomentose stipules, andfewandshorter bracts.
Lasianthuslongissimus H. Zhu,spec. nov. —Fig. 2
Proximus L. lancefolioHook.f.,sedfoliisminoribus,apicelongicaudis,nervis5-binatis,
lobis calycis subspathulatistubo longioribusdiffert. Similis L. japonico Miq. subsp.
longicaudo(Hook.f.)H.Zhu,sednervis 5-binatis,cymis sessilibus. lobis calycis 5sub-
spathulatis tubo longioribus differt.—Typus: P.K. Loc et al.CBL 2055 (holoAAU),
Vietnam,HaGiang,23° 56'N, 105° 13'E, 1100-1200 malt.,inprimary evergreenbroad-
leaved wet montaneforest,3 May 1999.
Shrub,2-3 m high; branchlets slender, terete, c. 1.5 mmdiam., puberulous onthe
youngestpart, glabrescent, dark-brown.Stipules very small, broadly triangular,c. 0.5
mmlong, puberulous. Leaveslanceolate, 10-16by 1.2-2cm,chartaceous, dark-brown
indesiccate, glabrous exceptpuberulous midribandnerves beneath,base acuminate
toacute,apexlong-caudate, margin slightly undulate,midribslightly depressedabove,
prominentbeneath,nerves depressedabove,prominentbeneath,5pairs,nervulesfaint
above, conspicuous beneath, parallel, glabrous; petioles 5-6 mmlong, puberulous.
Flowers in axillary, sessile fascicles; bracts inconspicuous, very small, 0.5-1 mm
long;calyx tubec.2mmlong, sparsely puberulous onexternal surface, calyx lobes5,
rare6, subspathulate toobovate,c. 3mmlong, sparsely puberulous onexternalsurface;
corollabud densely pubescent onexternal surface; stigma lobes 5; ovary 5-locular.
Drupes not seen.
398 BLUMEA Vol. 47, No. 2, 2002
Fig. 2.Lasianthus longissimusH. Zhu, showingholotypewith enlargedinflorescence (P.K. Loc
etal. CBL 2055).
H.Zhu & M.C. Roos: Three new species ofLasianthus from Vietnam 399
Fig. 3.Lasianthus oblongilobusH. Zhu,showingholotypewithenlarged axillaryflower (L. Aver-
yanovet al.HN4153).
400 BLUMEA Vol. 47, No. 2, 2002
Distribution—North Vietnam,known only fromthe typelocality.
Habitat&Ecology —Inprimary evergreenbroad-leavedverywet montane forest,
on very steepshaleslopes between 1100-1200m altitude.Flowering: May.
Note—Thisspecies isrelatedtoL.lancifolius Hook.f.Itdiffersfromthe latterby
having relatively small leaveswith 5 pairs ofnerves and along-caudate apex, and
subspathulate calyx lobes which are longer than the tube (L. lancifolius Hook.f.
hasrelatively big leaves with9pairs ofnerves andalong-acuminate apex, andsub-
ulatecalyx teeth whichare conspicuously shorterthan thetube). Itis alsosimilar to
L. japonicus Miq.subsp. longicaudus (Hook.f.) H.Zhu,butthelatterdiffersinhaving
leaveswithnumerousslendernerves, short-peduncled cymes, 4-merousflowers,and
acalyxwith 4minutely triangular teethwhichare shorterthan the tube.
Lasianthusoblongilobus H.Zhu,spec. nov. —Fig. 3
Proximus L. myrtifolio Ridl.,sed foliis majoribus,nervis subtus mine prominentibus,
ebracteis,lobis calycis oblongis longioribusdiffert.—Typus: L. Averyanovetal. HN
4153 (holoAAU),Vietnam,Khanh Hoa, 12° 11'N, 108° 43'E, 1500-1600 malt., in
broad-leaved cloud forest,22 April 1997.
Shrub,2-2.5m high;branchletsterete,compressed intheyoungestpart, striate,gla-
brous. Stipules small, broadly triangular, c. 0.5 mm long, hirsute. Leaves elliptic-
lanceolate,7-9by 2-3cm,coriaceous, glabrous, baseacute,apexacuminate,margin
recurved, midribdepressed above,prominent beneath,glabrous, nerves plain above,
prominent beneath, 6pairs, glabrous, nervules obscure above, prominent beneath,
subreticulate, glabrous;petioles 5-10mmlong, glabrous. Flowerssessile, solitary in
leafaxils; bracts absent; calyx campanulate, calyx tubec. 1.5 mmlong, pubescent,
calyxlobes 5 or6, oblong, 2by 1-1.5mm,puberulous onexternalsurface, pubescent
oninternalsurface(especially thelowerpart); corolla(tube andlobestogether) c. 7
mm long, densely pubescent onexternal surface, corollalobes4, densely pubescent
onexternal surface, floccose on internalsurface; stamens 4,inserted inthethroatof
corolla, filamentsshort, anthers oblong, c. 0.6mm long; style c. 4mmlong, with 4
linearstigma lobes; ovary 4-locular.Drupes not seen.
Distribution—SouthVietnam,known only fromthetype locality.
Habitat&Ecology — In montane cloudforest.Flowering: April.
Note— This species has glabrous branchlets andleaves, sessile solitary flowers,
bractsabsentandoblong calyx lobeswhichseparateitfromotherVietnameseLasian-
thusspecies. Itis closely relatedtoL. myrtifoliusRidl.fromwesternMalesianmoun-
tains. It differs from the latterby having relatively big leaves with less prominent
nerves on lower surface, absent bracts and longer oblong calyx lobes. Lasianthus
myrtifolius Ridl.hasrelatively smallleaveswithconspicuously prominent nerveson
bothsurfaces, smallbractsandshortertriangular calyx lobes (c. 1 mmlong).
ACKNOWLEDGEMENTS
Thisresearch wassupportedbyagrantfrom NWOofthe Netherlands (grantno.B 85-340)and
grantsoftheChinese AcademyofSciences forTopOneHundred YoungScientistsandtheproject
98C096MofYunnanScience Foundation. WethankProf.K.Larsen andthe Herbarium oftheUni-
H.Zhu & M.C. Roos: Three newspecies ofLasianthus from Vietnam 401
versity ofAarhus (AAU)forsendingspecimens onloan. WearegratefultoProf. P.Baas,Dr. C.E.
Ridsdale and Dr. DingHou for their greathelp in the research and be able to use Herbarium,
Library andresearch facilities oftheNationaal Herbarium Nederland,UniversiteitLeidenbranch,
and wearegratefultoDr. J.F.Veldkampforhisgreathelp inthe botanical nomenclature. We also
thanktwo anonymous reviewers fortheircomments onthis article.
REFERENCES
Drake,C.E. 1895.Contribution alaFlore du Tonkin. Journal deBotanique(Paris)IX:234-241.
Pitard,J.1924.Rubiaceae. In:H.Lecomte (ed.),Floregeneraledel'lndo-Chine 3,fasc.3:371-399.
Masson etCie,Paris.