Another two new species of Dimeria (Poaceae) from Kerala, India

6 Pages·1996·1.1 MB·English

by  Ravi, N

BLUMEA 41 (1996) 251-256
Anothertwo new species of Dimeria (Poaceae)
fromKerala, India
N.Ravi
TropicalBotanicGarden and ResearchInstitute,Palode 695562,Kerala,India
Summary
TwonewspeciesofDimeria R.Br.viz.,D.copeiandD.kalavoorensis aredescribed andillustrated.
DimeriaR.Br., atropical andsubtropical genusofover 45 species isrepresented in
Indiaby 32species ofwhich 19 occur in the state ofKerala(Sreekumar & Nair,
1991;Ravi& Anilkumar, 1992;Ravi, 1995).
The author, during thecourse ofcollecting grasses from the coastaldistrict of
Alappuzha, Kerala, collectedspecimens oftwodistinct speciesofDimeriafromthe
campusofAll IndiaRadioStation inKalavoor,near Alappuzha Town.Aftercritical
study withthehelpofDr. ThomasA.Cope (K), they were identifiedas undescribed
species. They aredescribedandillustratedhere.
Dimeriacopei Ravi, spec. nov. —Fig. 1
Dimeria lawsonii (Hook, f.)C.E.C.Fisch.affinis,seddiffertculmisrobustis,racemis 1vel
2(vel3)longioribusdense sericeis,rhachidi sine allis,spiculis majoribus,7.5-8 mmlon-
gis, callo longioremanifesto pilis longioribus, glumisplus sericeis, glumasuperiorelate
alata omnino secus carinam, arista longiore, 12-14 mm longa,antheris majoribus. —
Typus: Ravi 3655, 3Dec. 1992 (TBGTholo;K, KFRI,MH iso),India,Kerala,Alappuzha
District, Kalavoor.
Annualerectrobustherb.Culmsbranchedand tufted, upto 75 cm tall, nodesbeard-
ed. Leavesall along the culm; sheaths keeledon theback, broadly hyaline on the
margins, glabrous, theuppermostthe longest, upto 10cm long,often with a rudi-
mentaryblade; bladelinear,up to22 cmx2mm, shortly narrowedtothebase, acu-
minateattheapex, mid-ribbroadly flattenedaboveandkeeledbelow, sparsely beset
withlongbulbous-basedhairs onthemargins, scaberulous onthemargins towards
theapexandbase; ligule membraneous,fimbriate-truncateattheapex, upto 1 mm
long. Racemes 1 or2(or 3), rhachis moreorless straight, triquetrous, flattenedon
theback, upto 10cm long,0.6-0.75mm wide, densely ciliateonthemargins, gla-
brousorvery sparsely short-ciliateontheback, sometimeslongitudinally ridged with
sparse shortcilia ontheface; pedicels 0.4-0.5(-0.75) mm long, obliquely concave
atapex, ciliateonboth sides, densely soontheoutside. Spikelets oblong-elliptic in
profile, 7.5-8 mm long including theawn ofthe upperglume, callus prominent,
0.6-0.8mmlong, callushairsupto 1 mmlong.Lowerglume subcoriaceous, linear-
252 BLUMEA —Vol. 41, No. 1, 1996
Fig. 1.Dimeria copeiRavi.a.Habit;b.leaf; c.rhachis;d.spikelet; e.lower glume;f.upper glume;
g.lower lemma;h. upper lemma;i. upper palea;j.lodicules,stamens and pistil; k. grain(allRavi
3655).
N.Ravi: Two new species ofDimeria 253
oblong, 5.5-5.75 x0.6-0.7 mm, acuminate-aristateatapexwith thearista0.5-0.6
(-0.75) mmlong, keeledon theback, keel narrowly winged 1/3towards theapex,
ciliateall over, densely so onthekeelexcept towardsthescaberulousapex. Upper
glume oblong-elliptic, 7-7.25 x 1.25 mm,acuminate-awned atapex, awn (0.75-)
1-1.25mmlong,scaberulous, keeledon theback, broadly winged allalong thekeel,
wing c. 0.4mm wide, densely long-ciliateon the backexcept towardsthescaberu-
lousapex, sparsely shortciliateonitssides with afew long hairs towardstheapex,
sidessubcoriaceous, ciliatein abroad longitudinal lineclose to thekeel, margins
hyaline, shortciliateinthemiddle.Lowerlemmaoblanceolate, c. 3mmlong, cune-
atetowards thebase, acute atapex, hyaline, 1-nerved, ciliateonthemargins above
themiddle,andepaleate. Upper lemmaoblanceolate, 3.5-4x0.75 mm(when fold-
ed), hyaline, awned fromthe sinus ofthebifid apex; awn 12-14mmlong witha
3.5-4mmlong column,scaberulous. Paleasmall, lanceolate, c. 0.75mmlong,pa-
pillate in theupper half.Lodiculescuneate,c. 0.25 mm long. Stamens 2; anthers
1.25-2mm long. Grainoblong-elliptic, flattened,2.5-2.75x 0.3mm, subacuteto
acuteandapiculate atapex.
Note —Dimeria copei isalliedtoD. lawsonii(Hook, f.) C.E.C. Fisch. butdif-
fersfromthe latterin having robust culms, densely silky 1 or2 (or 3) and longer
racemes, wingless rhachis, larger spikelets, larger prominent callus with longer
hairs, moresilky-hairy glumes, upperglume broadly winged allalong itskeel, lon-
gerawn, andlargeranthers.
DimeriakalavoorensisRavi, spec.nov. —Fig. 2
Dimeria copeiRavi etD. lawsonii (Hook,f.) C.E.C.Fisch. affinis,a prioridiffertculmis
solitariis eramosis filiformibusque,racemis solitariis brevioribus,rhachidi angustealata,
spiculisquebrevioribus cum partibusparvioribus; aposteriori differt in habitu,rhachidi
angustiore,pedicellis longioribus, callo longioremanifesto pilis longioribus,glumisplus
sericeis, gluma superiore late alata omnino secuscarinam. —Typus: Ravi 3654,3 Dec.
1992(TGBTholo;K,KFRI, MHiso),India,Kerala,AlappuzhaDistrict,Kalavoor.
Annualerectherb. Culmssolitary, unbranchedand filiform, upto45cm long, rarely
rooting atthelowernodes;nodes bearded.Leavesallalong theculm; sheathsclosely
enclosing the culm, the uppermostthelongest, up to6 cm long, keeledon theback
and glabrous; bladelinear,upto 5 cm x2 mm,shortly narrowedtothebase,acumi-
nate atapex,besetwith sparse,long,bulbous-basedhairson themargins, especially
towardsthebase, 5-veined, outer lateral veins almostalong themargins, mid-vein
flattenedaboveand keeledbelow; ligule membraneous,fimbriate-truncateatapex,
c.0.5mm long.Raceme solitary; rhachis moreorless straight, triquetrous, flattened
on the back, 0.5-4cm x 0.5-0.6 mm,narrowly winged on the margins, margins
ciliate; pedicel 0.5-0.6mmlong, concave atapex, densely ciliateon the outside,
sparsely soontheinnerside.Spikelets elliptic-acuminate inprofile,6-6.5 mmlong
including the awn oftheupperglume; callus 0.5-0.6mm long, callus hairs up to
1 mmlong.Lowerglumesubcoriaceous, narrowly elliptic-oblong, 4.5-5x0.5mm,
acuminate-aristateatapex, arista upto0.5 mmlong andscaberulous, keeledon the
back, keel narrowly winged abovethe middle, silky-ciliate on thesides except to-
wardstheapex and margins, densely soon the keelexcept towards theapex. Upper
254 BLUMEA —Vol. 41, No. 1, 1996
Fig.2.Dimeriakalavoorensis Ravi.a.Habit;b. leaf;c.rhachis; d.spikelet;e.lower glume;f. upper
glume; g.lower lemma;h. upper lemma;i. upper palea;j. lodicules,stamens and pistil; k. grain
(allRavi3654).
N.Ravi: Two new speciesof Dimeria 255
glume subcoriaceous, elliptic-oblong, 5-5.25 x 1 mm, acuminate-awnedat apex,
awn upto 0.75mm long andscaberulous, broadly winged all along thekeel, silky-
ciliatealloverthewing, densely so onthebackofthe wingexcept towardstheapex,
sides ciliateinabroad longitudinal lineclose tothekeelandthemiddle,margins cili-
ate inthemiddle.Lower lemmaoblanceolate, c. 2.5 mmlong, cuneate towards the
base, acuteat apex, hyaline, 1-nerved, ciliateonthemargins above themiddleand
epaleate. Upper lemmaoblanceolate, c. 3x0.5mm (when folded), hyaline, awned
fromthesinusofthebifidapex; awn9.5-11.5 mmlong with a3-3.5 mmlong col-
umn.Palea small, elongate-triangular, c. 0.75mm long, hyaline, papillate towards
the upperhalf.Lodicules very thin,triangular-oblong, acute at apex, c. 0.25 mm
long. Stamens2; anthers 1-1.5mm long. Grainelliptic tooblong-elliptic, flattened,
1-1.5mmlong, acute atapex.
Note— DimeriakalavoorensisisalliedtoD.copei RaviandD.lawsonii(Hook, f.)
C.E.C.Fisch. butdistinct from the former in having solitary unbranchedfiliform
culms, solitary shorter racemes, narrowly winged rhachis,andsmallerspikelets with
smallerparts, and fromthelatter inhabit,narrower rhachis, longerpedicels, longer
prominent calluswithlonger hairs,moresilky-hairy glumes, andupperglumebroad-
ly winged allalongitskeel.
Thelatestwork onDimeriaoftheIndiansubcontinentisthatofBor(1960). Thetwo
newtaxa describedhere,bothallied toDimerialawsonii, canbeaccommodatedinthe
key given by Bor, alongside lead number27 (Bor, 1960: 138), as keyed outbelow.
27. Upperglumewinged frombasetoapex:—
28. Callusvery short,0.4mm long or shorter; wing oftheupperglume tapering
tobase D.lawsonii
28. Callus long, 0.5-0.8 mm long; wingofthe upperglume more or less uni-
formlybroad:
—
29. Culmsfiliformandsolitary; raceme 1;rhachis shorter andnarrower, upto
4cm x0.5-0.6mm,triquetrous-flattened, wingedonthemargins; spike-
letssmaller, 6-6.5 mmlong; callus shorter, 0.5-0.6 mmlong; awnofthe
upperglume shorter, upto0.75mmlong D.kalavoorensis
29. Culmsrobust,tuftedandbranched;racemes 1-3;rhachis longer andbroad-
er, up to 10cm x 0.6-0.75mm,triquetrous flattened, not winged onthe
margins; spikelets larger,7.5-8 mm long; callus longer, 0.6-0.8 mm
long; awnoftheupperglume longer, 0.75-1.25mm long .... D. copei
Dimeriacopei andD. kalavoorensisformextensive patches, pureandmixed, inthe
typelocality. Thepurepatches ofthelatterappearsomewhatyellowish greenduring
flowering. Thetype locality, whichis anopen sandy place, becomes water-logged
during the monsoon and shows such associate grassspecies as Ischaemumranga-
charianumC.E.C.Fisch.andPanicumrepensL.and dicotspecies as theinsectivor-
ous DroseraindicaL.andUtriculariareticulataSmithandtheroot-parasitic Centran-
theracochinchinensis(Lour.)Merr.
Dimeriacopei is namedafterThomasA. Copein recognitionofhis contributions
to agrostology andD. kalavoorensisis namedafterits typelocality.
256 BLUMEA Vol. 41, No. 1, 1996
ACKNOWLEDGEMENTS
The authoris thankful toDr.Thomas A.Copeforhis help in confirmingthe identity ofthe new
taxa, Dr.N.C. Majumdar, Calcutta,formerly ofthe Botanical Survey ofIndia,forproviding the
Latin diagnoses,Dr. P.Pushpangadan,Director,TropicalBotanical Garden andResearch Institute
(TBGRI), Palode, forprovidingfacilities for carrying outthe work and Mr. K.P. Pradeepkumar,
Artist, TBGRI,for makingthedrawings.
REFERENCES
Bor, N.L. 1960.TheGrasses ofBurma,Ceylon,India and Pakistan: 136-138. PergamonPress,
Oxford.
Ravi,N. 1995.Twonewspecies ofDimeria R.Br.(Poaceae)fromKerala,India. Rheedea 5: 37-42.
Ravi,N„ & N. Anilkumar. 1992.New and interestingspecies ofDimeria R.Br. (Poaceae) from
Kerala,India. Rheedea 2: 101-107.
Sreekumar,P.V.,& V.J.Nair. 1991.FloraofKerala- Grasses: 80-81. Botanical Survey ofIndia,
Calcutta.