Download A New Species of Jatropha (Euphorbiaceae) from Nicaragua

A NEW SPECIES
OF JATROPHA (EUPHORBIACEAE)
FROM NICARAGUA'
GRADYL.
WEBSTER2
ABSTRAcr
A new species,Jatrophastevensii,is describedfromcollectionsin Dept. Boaco in Nicaragua. It may
be assigned to subg. Curcas and appears relatedto Jatrophafremontioides,a species fromsouthern
Mexico. Jatrophastevensiirepresentsyet anotherextensionof the Mexican xerophyticelementinto
CentralAmerica, and the second recordforJatrophasubg. Curcas.
When JatrophacostaricensisWebster & Poveda was describedfromGuanacaste,Costa Rica,
some yearsago (Webster& Poveda, 1978), itwas
predicted that other xeric relict taxa mightbe
discoveredelsewherein CentralAmerica.Recent
botanical explorationin Nicaragua has disclosed
not only a numberof new populations of Jatropha podagrica Hook. in rockyareas in Dept. Esteli,but also on basaltic ridgesin Dept. Boaco a
species that appears to be undescribed.Unlike
J. podagrica, which belongs to subg. Jatropha
(Dehgan & Webster,1979), theplantfromBoaco
clearlyis referableto subg. Curcas.
beneath midriband secondariesraised, veinlets
prominent;marginsentire,eglandular.Monoecious; dichasia terminal,oftenpaired, with peduncle 1-2.5 cm long, branches hispidulous;
bracts oblong-lanceolate to oblanceolate, glabrous or tomentulose,lower ones 4-5 mm long
and 1.2-1.3 mm broad; pistillateflowers0-2 per
dichasium,at lowernodes; staminateflowers1015,at upperdichotomies.Staminateflower:pedicel 0.5-0.8 mm long,articulatedat base; sepals
5, lanceolate,obtuseor subacute,entire,glabrous
or hirsutulous,2.5-4.8 mm long, 1.2-2 mm
broad; petals 5, pale green, oblong, glabrous
abaxially,copiouslyhirsutulousadaxiallyin lowJatrophastevensiiWebster,sp. nov. TYPE: Nic- er half,5.5-6 mm long, coherentinto a tube in
aragua, Dept. Boaco, 1.6 km SW of Santa lower 1/3,midribwith several sharplyascending
Cruz, low ridgeofbasaltic lava, 140-160 m, lateralsthatdichotomizedistally;disk glands 5,
12024'N, 85050'W, 7 June 1984, W. D. Ste- cubical, glabrous,0.5-0.6 mm high;stamens 10,
vens 22902 (MO, holotype;DAV, isotype; biverticellate,monadelphous below into a slenadditional isotypes to be distributed). It der column 3-4 mm high,outerstamenson filshould be noted thatthe typecollectionin- aments ca. 1 mm long. Pistillateflower:pedicel
cludes both glabrous and pubescent speci- glabrousor tomentulose,becoming3-1 1 mm long
mensand was apparentlygatheredfromsev- in fruit;sepals 5, ellipticor lanceolate,obtuse or
eral individuals.
subacute, becoming in fruit5.5-6.5 mm long,
2.5-3.8 mm broad; petals 5, ovate at base taAbJ.olivaceadiffert
dichasiomenor,
minorestipulis
obsoletis,fohiis
nonglanduligeris;peringto oblong obtuse tips,pale green,ca. 5.8integris
marginibus
ab J.alamaniifoliiselobatis,sepalisminoribus,
petalis 6 mm long,4-4.2 mm broad, hirsutulousadaxtantum1/3longitudinis
coalitis;ab J.fremontioide
foihis ially,coherentin lower 1/3;disk dissected into 5
dichasiononcapituliforme.
acuminatis,
lobes; ovary smooth,glabrous,sharplycarinate,
Deciduous shrub to 3 m high; twigs terete, 3-locular;stylesca. 3 mm long,connatein lower
greyish-or reddish-brown,glabrous or hispidu- 1/3,erect,scarcelybifid;stigmasdilated, elliptic,
lous, exudingcloudy latex when cut. Leaves al- 0.7 mm long, 0.3 mm broad. Capsule smooth,
ternateor clusteredon spur shoots; stipulesob- 3-lobed,prominently3-carinateon back ofcocci,
solete; petioles slender, 5-25 mm long; blades 1.5-1.6 mm in diameter;seeds ellipsoidal, ca. 9
thinlychartaceous,ovate contractedto an acu- mm long,smooth;carunclebrownish,deeplyflaminatetip,cordateat base, loosely tomentoseto bellatelylobed, 2.5 mm long, 4 mm broad.
glabrous beneath, 2-4 cm long, 1-3 cm broad,
Additionalcollectionsexamined. NICARAGUA.
palmately 5-veined at base, brochidodromous, BOACO:1 kmE of Santa Cruz, 200 m, Moreno22467B
I
2
I wish to thankMs. Lynn Gillespie forthe photographof the typecollection.
Departmentof Botany,Universityof California,Davis, California95616.
ANN. MISSOURI BOT. GARD. 74: 117-120. 1987.
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1mmI
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FIGURE 1. Flowers and leaf of Jatrophastevensii(Stevens22902). -A-C. Staminateflower.-A. Sepal. -B.
Petal. -C. Androeciumand disk-segment.
-D-F. Pistillateflower.-D. Sepal. -E. Petal.-F. Gynoecium.-G.
Leaf.
(MO). Matagalpa: San Juanillo,8 km SE of Ciudad
Dario, 500 m, Grijalva2599 (DAV, MO).
Jatrophastevensii,named in honor of Warren
Douglas Stevens,the leading studentand collectoroftheNicaraguanflora,belongsto subg. Curcas (Adans.) Griseb. by virtueof its flowerswith
entireimbricatesepals, coherentpetals,and androeciumof 10 monadelphousstamens(Dehgan
& Webster,1979). Withinsubg. Curcas, it is referableto sect. PlatyphyllaeDehgan & Webster
because of its 3-locularcarinatefruitsand biseriateanthers.However,it is divergentfrommost
species of sect. Platyphyllaein havingelongated
seeds with a prominentcaruncle. As noted by
McVaugh (1945), J.fremontioidesStandl. from
Oaxaca differs
fromotherspecies ofsubg. Curcas
in its prominentlycarunculate seeds. Furthermore, Dehgan (1980) has indicated that J. fremontioidesis distinguishedby anisocytic stomata, a featureunique in the genus.
The prominentlycarunculate seeds, monoecious flowerproduction,and small entirecordate
leaves linkJ. stevensiiwithJ.fremontioidesand
indicate that the latteris the closest relative of
thenew species. The two speciesforma subgroup
of sect. Platyphyllaediffering
frommore typical
species such as J. platyphylla,J. alamanii, and
J. ciliata, which have largermore-or-lesslobed
leaves, flowersproduced dioeciously,and seeds
with small caruncles. Nevertheless,the staminate and pistillateflowersof such species as J.
ciliata are quite similar overall to those of J.
stevensiiand J. fremontioides,and the preponderance of evidence does not seem to compel
of sect.
any modificationsin thecircumscription
Platyphyllaeat this time.
The discoveryofJ.stevensiiin Nicaraguabrings
to threethe number of endemic Central American species of Jatropha: J. podagrica Hook.
(eastern Guatemala to Nicaragua), J. stevensii
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1987]
FiGURE2.
WEBSTER-JATROPHA
Photographof type collection of Jatrophastevensii(Stevens 22902), left-handglabrous
branchwithpistillate
pubescent
flowers.
flowers;
withcapsuleand staminate
right-hand
(Nicaragua), and J. costaricensisWebster& Poveda (Guanacaste, Costa Rica). These speciesbesubgeneraand sections,J.
long to two different
podagnca in subg.Jatrophasect. Peltatae and J.
stevensiiand J. costaricensisin subg. Curcas sect
119
asnch
However, as notedby Websterand
Platyphyllae.
Poveda (1978), J. costaricensisis most closely
related to J. alamanii Muell. Arg. of southern
notto J.stevensii.
Mexico (Oaxaca) and therefore
The CentralAmericanspecies ofJatropha
ap-
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120
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pear to representa depauperateextensionof the vasion of plants ancestralto J. podagrica must
largeassemblage of endemic species in southern be more recent,and indeed perhaps subsequent
Mexico, as remarkedby Webster and Poveda to the closing of the Panamanian gap.
thatthefloristicbreakfor
(1978). It is interesting
LITERATURE CITED
Jatrophacomes not at the Isthmus of Tehuantepecbut in Guatemala; however,thereis clearly DEHGAN, B. 1980. Application of epidermal morphologyto taxonomic delimitationsin the genus
a decline in diversityeast of the Isthmus.
JatrophaL. (Euphorbiaceae). Bot. J.Linn. Soc. 80:
In contrastto studies such as that of Savage
257-278.
(1982) on vertebratedistributionsin Mesoamer1979. Morphology and
& G. L. WEBSTER.
ica, thereis clearlyno ancientCentralAmerican
infragenericrelationshipsof the genus Jatropha
(Euphorbiaceae). Univ. Calif. Publ. Bot. 74: 1-73.
centerforxericEuphorbiaceae such as Cnidoscolus, Jatropha,and Manihot. Instead, in Meso- GENTRY, A. J. 1982. Neotropical floristicdiversity:
phytogeographicalconnections between Central
americanJatrophatherehas been an invasion of
and South America, Pleistocene climatic fluctuaone species of subg. Jatrophafromthe south (J.
tions,or an accidentofthe Andean orogeny?Ann.
podagrica) and two species of subg. Curcas from
Missouri Bot. Gard. 69: 557-593.
the north(J. costaricensisand J. stevensii).Gen- MCVAUGH, R. 1945. The genusJatrophain America:
principal intragenericgroups. Bull. Torrey Bot.
try( 1982) considersthatxericMesoamericantaxa
Club 72: 271-294.
are ultimatelyof southernorigin.However, for SAVAGE, J.M. 1982. The enigmaoftheCentralAmerJatropha subg. Curcas and other distinctive
ican herpetofauna:dispersalsor vicariance?Ann.
Missouri Bot. Gard. 69: 464-547.
Mexican xerophytetaxa such as the Fouquieriaceae, this migrationfromthe south must have WEBSTER, G. L. & L. J. POVEDA. 1978. A phytogeographicallysignificantnew species of Jatropha
been so ancientthatthese taxa may be regarded
(Euphorbiaceae) from Costa Rica. Brittonia 30:
as autochthonousto Mexico in terms of their
265-270.
evolutionarydiversification.In contrast,the in-
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