Rubiacearum Americanarum Magna Hama, Pars XVII. A new species and four new combinations in mesoamerican Rondeletieae (Rubiaceae)

2005·3.6 MB·

by  D H Lorence

Rubiacearum Americanarum Magna Hama, Pars XVII.
A New Species and Four New Combinations in
Mesoameriean Rondeletieae (Rubiaceae)
David //. Licence
National Tropical Botanical Garden, 3530 Papalina Road, Kalaheo, Hawaii 96765, U.S.A.
[email protected]
ABSTRACT. Studies for a forthcoming treatment of from Mexico to South America; and Rogiera Plan¬
Rubiaceae for the Flora Mesoamericana project re¬ chon, with 18 species ranging from Mexico to Pan¬
vealed an undescribed species from Honduras and ama (Mabberley, 1997; Lorenee & Taylor, in prep.).
also the necessity for four new combinations in Initial cytological evidence based on investigations
Rondeletieae. The new species Arachnothryx nel¬ of two species per genus revealed base numbers of
son ii Lorenee is described from Honduras. It is re¬ n = 9 for Arachnothryx, n = 10, 11 for Rogiera.
lated to the glabrous Mexican species A. purpurea and n — I I, 14 for Rondeletia s. str. (Kiehn, 1995).
(Lorenee) Bothidi from which it differs in having More recently, Borhidi and collaborators have
leaves sparsely strigillose on the costa, veins, and described several small segregate genera in tbis al¬
margins, flowers with a strigillose hypanthium and liance in Mexico and Mesoamerica based on mor¬
calyx, white externally strigillose corollas, and phological criteria, including Javorkaea Borhidi A
subglobose capsules. In addition, the following new Jarai-Komlodi, Rennistipula Borhidi, and Rovean-
combinations are proposed in Arachnothryx and thus Borhidi (Borhidi & Jarai-Komlodi. 1983; Bor¬
Rogiera: Rondeletia myriantha Standley & Steyer- hidi, 2003, 2004). Rennistipula was described to
mark var. armentalis L. 0. Williams is elevated to accommodate three species with reniform stipules
species level as Arachnothryx armentalis (L. 0.
that Borhidi had previously transferred to Arach¬
Williams) Lorenee; Rondeletia hondurensis Donnell
nothryx: A. costaricensis (Standley) Borhidi, A. g<d-
Smith is transferred to Arachnothryx as Arachnoth¬
eottii (Standley) Borhidi, and A. izabalensis (Stand-
ryx hondurensis (Donnell Smith) Lorenee; Ronde¬
ley & Steyermark) Borhidi. In addition, Borhidi
letia megalantha is transferred to Arachnothryx as
(2004) described Roveanthus to accommodate two
Arachnothryx megalantha (Lorenee) Lorenee; Ron¬
species he had formerly included in Rogiera: R.
deletia standleyana A. R. Molina is transferred to
strigosus (Bentham) Borhidi and R. suffrutescens
Rogiera as Rogiera standleyana (A. R. Molina) Lor-
(Brandegee) Borhidi. Pending further molecular
ence; and Rondeletia ovandensis Lundell is reduced
and phylogenetic studies covering a broad range of
to synonymy under Arachnothryx armentalis.
Rondeletieae species, I believe it is premature to
Key words: Arachnothryx, Javorkaea, Mesoam-
recognize these new genera and prefer to retain
eriea, Rogiera. Rondeletia. Rondeletieae, Rubi¬
these species in Arachnothryx and Rogiera, respec¬
aceae.
tively.
Recent molecular-phylogenetic data from /rrcL-F
As interpreted in the broad or traditional sense,
cpDNA gene sequencing suggest that Rondeletia
Rondeletia s.l. comprises approximately 230 to 250
s.l. is polyphyletic, and that Arachnothryx and Ja¬
species of shrubs and small trees restricted to the
vorkaea are closely related to each other and to
tropical regions of Mexico. Central and South
America, and the Antilles. However, the genus dis¬ Gonzalagunia Ruiz & Pavbn (also Rubiaceae: Ron¬
plays considerable morphological variation and has deletieae), but less closely so to Rogiera and Ron¬
been split into segregate genera by various authors, deletia s. str. (Rova et al., 2002). However, only a
most often utilizing morphological characters (for small number of species in the Rondeletia alliance
further discussion see Borhidi, 1982, 1987, 2001: have been sampled thus far for molecular studies;
Borhidi A Fernandez Zequeira, 1981; and Lorenee, more importantly, virtually none of the critical spe¬
1991). I he three principal segregate genera are: cies of Arachnothryx from Mexico and Central
Rondeletia s. str., comprising ca. 140 species main¬ America with unusual floral and seed morphologi¬
ly in the Antilles (four species in Mesoamerica); cal characters that overlap the generic boundaries
Arachnothryx Planchon with ca. 80 species ranging proposed by Borhidi and others have been sampled.
Novon 15: 447-451. Published on 21 September 2005.
448 No von
These include species such as Arachnothryx delimit Copan ruinas on road to Agua Caliente from
(Donnell Smith) Borhidi and A. hondurensis, whose Copan ruinas and 2-3 km W of Los Zapotes
deviating characters are noted in the key below. school, 950-1050 m, 14°58'N, 89°10'W, 30
Species comprising the segregate genera Rennisti- Apr. 1996 (11. fr), T. Hutchins 993 (holotype,
pula and Roveanthus also remain unsampled. Fur¬ MO; isotypes, BM. LAP. MEXU, PTBG). Fig¬
ther cytological, morphological, phylogenetic, and ure I.
molecular studies are clearly needed to satisfacto¬
rily resolve the systematics of this complex. Haec species Arachnotrychi purpureae affinis, sed ab ea
lamina foliari secns costam venas marginemque parcestri-
In light of available evidence it was decided to
gillosa. hypanthio calyceque strigillosis, corolla alba extus
recognize three segregate genera in the broader
strigillosa, atque eapsula subglobosa differt.
Rondeletia alliance (i.e., Arachnothryx, Rogiera,
and Rondeletia s. sir.) lor the Flora Mesoamericana Small Irees 3—8 m tall, the leafy twigs slender,
treatment. During the course of preparing accounts 1- 1.8 mm diam., terete, glabrous, drying dark
of these genera, collections representing an unde¬ brown, wrinkled, the internodes 0.7—10 cm long.
scribed species from Honduras were encountered. Leaves opposite, those of a pair at a node aniso-
In addition, four new combinations in Arachnothryx phyllous or subequal, one up to 50% larger than
and one in Rogiera are required. A full treatment the other; lamina ovate-elliptic, elliptic, oblong-el¬
ol the Mesoameriean Rubiaceae will be given in liptic or oblaneeolate-elliptic, 4-1 1 X 1.5—3.5 cm,
the forthcoming treatment for Flora Mesoamerieana the apex abruptly acuminate or caudate, the acu¬
by David Lorence and Charlotte M. Taylor (Lorence men 1-1.5 cm long, often falcate, the base euneate
& Taylor, in prep.). to acute, often unequal-sided, drying membrana¬
ceous to thinly chartaceous, greenish brown, adax-
Kky to thk Three Genera in the Rondeletia s.e. Ai - ially sparsely strigillose on costa and secondary
i.iance in the Mesoamerican Recion veins, abaxially glabrous or sparsely strigillose on
la. Lobes ol calyx and corolla usually 4 (corolla costa and veins, the secondary veins 3 to 7 pairs,
lobes 5 and calyx lobes 5 to 7 in A. hondurensis, arcuate, prominulous on both surfaces, eucampto-
calyx lobes rarely 5 or 6 in A. deamii); corolla
dromous, the axils barbate and domatiate, the ve¬
throat glabrous or white papillose-puberulent in
and around throat, not yellow or white barbate nation visible to quaternary order on both surfaces,
(except in A. hondurensis), lacking a conspicuous the margins sparsely strigillose-eiliolate; petioles
fleshy ring around throat, tube internally pubes¬ 2— 10 mm long, 0.5—0.8 mm diam., glabrous or
cent in basal portion; capsule dehiscence locu-
adaxially strigillose; stipules broadly to narrowly
licidal and often with some septieidal splitting;
triangular, acuminate, 0.8—2 mm long, ea. I mm
seeds usually rhomboid, square, or triangular, not
winged or caudate (except fusiform and winged wide, externally sparsely strigillose, internally pi-
in 1. deamii. narrowly winged in A. costaricensis, losulous. Inflorescence terminal, corymbiform-cy-
A. galeottii, and A. izabalensis), the testa usually mose, triehotomous, 3-7 X 2.5—5 cm (including the
deeply foveolate-reticulate . Arachnothryx
corollas), sessile or the peduncle to 3 cm long, 12-
lb. Lobes ol calyx and corolla usually 5 (rarely 4 or
6 in some flowers); corolla densely yellow or to 27-flowered, the primary branches 3, ascending,
white barbate in and around mouth of tube, or 0.8—3.4 cm long, subequal or the central one lon¬
with a thickened fleshy ring around mouth of gest, unbranched or branching once again, ending
tube, tube glabrous within; capsule dehiscence
in 2- to 6-flowered cymules. the axes glabrous, flat¬
strictly loculicidal; seeds fusiform, caudate and
tened, bracteoles 0.8-3 mm long, linear-subulate,
winged at one or both ends (Rondeletia), or an¬
gular to rounded or suborbicular (Rogiera), the strigillose; flowers apparently distylous, subsessile
testa usually shallowly foveolate-reticulate. or on pedicels to 1.2 mm long, minutely bracteo-
2a. Corolla with a thickened, fleshy ring around late, the hypanthium ellipsoid, 1-1.2 X 0.6—0.8
mouth ol tube (also papillose or puberulent
mm, strigillose, the calyx limb lobed nearly to base,
in R. belizensis (Donnell Smith) Lorence);
seeds fusiform, caudate and winged at one calyx cup 0.3 mm deep, calyx lobes 4. strigillose,
or both ends (discoid with broad wing in R. unequal. I large and oblong or oblong-elliptic, 2—
belizensis) .Rondeletia s. str. 4.5 X 0.7—0.9 mm, the other 3 lobes much smaller,
2b. Corolla densely yellow or white barbate in
linear or subulate, 1—2.5 X 0.1 mm; corolla sal-
and around mouth ol tube; seeds angular
verform. while, the tube ca. 8 mm long, 0.6—0.8
and rounded to suborbicular, unwinged . . .
.Rogiera mm diam. medially, externally strigillose with as¬
cending hairs, internally hirtellous in basal 1/3,
I. Arachnothryx iielsnuii Lorence, sp. nov. distally glabrous, the lobes 4, oblong-elliptic, 1.2—
TV PE: Honduras. Copan: Montana Los Zapo- 1.5 X 1 — 1.2 mm. externally strigillose-setose, in¬
tes, mountain W of Los Zapotes, 18 km N ol ternally glabrous; short-styled flowers with stamens
Volume 15, Number 3 Lorence 449
2005 Mesoamerican Rondeletieae
Figure 1. Arachnothryx nelsonii Lorence. —a. Habit with inset showing abaxial leal surface details. —b. Flower, with
hypanthium bearing calyx lobes and style, and corolla tube opened to reveal stamens. —c. Two inflorescence evmules
with flowers in bud. —d. Disintegrating capsules showing vascular bundles. —e. Seed. —f. Node with stipule. All
drawn from the type, Han kins 993. Seale bar 5 cm in a; I cm in b, c, d; 0.5 mm in e; 1 mm in f.
included, sessile, attached ca. 1 mm below apex of Distribution and habitat. Known only from the
tube, the anthers ca. I mm long w ith style glabrous, departments of Copan and Cortes in Honduras
ca. 3.5 mm long with 2 linear stigma lobes ca. 1.5 where it occurs in montane evergreen wet foresl
mm long; long-styled flowers not seen. Capsules with Liquidambar. 950—1500 m in elevation. Col¬
subglobose, 3—4.5 mm diam., glabrate, slightly 1 »i- lected in flower in February and April, anil in fruit
silicate, weakly 6- to 8-ribbed, disintegrating with in April.
age to reveal vascular bundles; seeds subglobose- Etymology. This species is named for Hondur¬
angulate, 0.4—0.6 mm diam., the testa deeply retic¬ an botanist Cirilo II. Nelson in recognition of his
ulate, dark brown. contributions to the botany of Honduras.
450 Novon
Arachnothryx nelsonii seems most c losely related adaxially smooth and glabrous or at first sparsely
to the nearly glabrous Mexican species A. purpurea arachnoid-tomentose and soon glabrescent, inflo¬
(Lorence) Borhidi from which it differs in having rescences mostly longer than the subtending leaves,
leaves sparsely strigillose on the costa, veins, and and corolla lobes externally arachnoid-tomentose
margins, flowers with a strigillose hypanthium and hut lacking pilose-setose triehomes. Arachnothryx
calyx, corolla white with an externally strigillose armentalis occurs in Mexico (Oaxaca, Chiapas) and
lube and externally strigillose-setose lobes, and Guatemala in mesic and cloud forests at 1 100—
subglobose capsules. I 700 m in elevation.
Raralype. HONDl HAS. (lories: Montana de I.a Ni- Representative specimens examined. MEXICO. Oaxa¬
eve, lado SO del Caserfo El Tapiquilar, 20 km S de San ca: Sierra Mazateea. Mun. Huautla de Jimenez, alrede-
Antonio de (lories. 2d Kel>. 1982 (fl), C. Nelson. J. Escobar ilores del Puente de Fierro en direccirtn a Sta. Marfa Chil-
& R. An,lino HOI) I (MO 4324692, PTBG, UN AII). chotla (7 km de Huautla de Jimenez por la carretera a
lentilIan—Mex 132), Munn-Estrada & Mendoza 1204
2. Arachnothryx armentalis (I.. (). Williams) (I’TIIG). Chiapas: from El Triunfo to El Paval, S slopes
of Sierra de Soconuseo, Xolocotzi A Sharp X. 489 (MO).
Lorence, comb, et slat. nov. Basionym: Ran-
GUATEMALA. Sail Marcos: above Finca el Porvenir on
deletia myrianlha Standley & Steyermark var.
“Todos Santos Chiquitos”, lower S-faeing slopes of Volcan
armentalis I.. 0. Williams, Phytologia 26: 127. Tajumulco, Steyermark 87096 (F).
1973. Arachnothryx myrianlha (Standley &
Steyermark) Borhidi var. armentalis (I.. ().
3. Arachnothryx hondurcnsis (Donnell Smith)
Williams) Borhidi, Acta Bot. Hung. 35: 310.
Lorence, comb. nov. Basionym: Rondeletia
1989. TYPE: Guatemala. (v)uiche: Nebaj, 5600
hondurcnsis Donnell Smith, Bot. Caz. (Craw-
It.. 22 Nov. 1934, A. F. Skutch I 776 (holotype,
fordsville) 27: 335. 1899. Javorkaea honduren-
K 81581 I, photos at MEXU, PTBG).
sis (Donnell Smith) Borhidi & J. komlodi. Acta
Rondeletia ovandensis l.undell, Wrightia 5: 326. 1976. Bot. Hung. 29: 16. 1983. TYPE: Honduras.
Syn. nov. Arachnothryx ovandensis (l.undell) Borhidi, Santa Barbara: Rfo Chameleeon, 300 m. Dee.
Acta Bot. Hung. 35: 310. 1989. TYPE: Mexico, 1888, C. Thieme 5267 (holotype, US 943502;
(lliiapas: Ml. Ovando near Eseuintla, 24 Oct. 1911.
isotypes, F. US [21).
E. Matilda 0007 (holotype, I.I., photos at MEXL .
I*TBG; isotypes, E. 1.1. not seen).
The segregate genus Javorkaea (Borhidi & Jarai-
V\ illiams (1973) described Rondeletia myrianlha komlodi. 1983) was described to accommodate
Standley & Steyermark var. armentalis (meaning Rondeletia hondurcnsis Donnell Smith, a species
“one ol a crowd") based on a single flowering spec¬ endemic to Honduras and recognized by Standley
imen. lie believed it represented a minor variant (1918) as comprising the monospecific but never
of Arachnothryx myrianlha (Standley X Steyer¬ validly published section Hondurenses Standley of
mark) Borhidi, from which it differed in having Rondeletia. Javorkaea was characterized similarly
leaves densely arachnoid-tomentose abaxially and to Standley’s Hondurenses by 1- to 3-lobed stipules
flowers with a sparsely arachnoid-tomentose hypan¬ with well-developed sheaths, I - to 3-storied inflo¬
thium and calyx limb and subequal calyx lobes. rescences, a 4- to 7-merous calyx, a large, slightly
Further study of additional collections has revealed zygomorphic 5-merous corolla with lobes puberu-
that A. myrianlha is characterized by having leaves lent basallv within, a subeapitate and bilobed stig¬
that are uniformly arachnoid-tomentose on both ma. a glabrous nectary disc, 4-eolporate pollen, ob¬
surfaces when young and soon glabrescent and its long hypanthium and capsule, capsule dehiscence
corollas externally strigillose-pilosulous, whereas at first loculicidal then septicidal and separating at
variety armentalis differs in having leaves adaxially base, and seeds as in Arachnothryx (Borhidi & Jar-
persistently hirtellous or seabrid and corollas ex¬ ai-komlodi, 1983). The subeapitate, shortly bilobed
ternally tomentulous on the tube ami pilose-setose stigma and 4-colporate pollen grains are distinctive
on the lobes. In view of these fundamentally dif¬ at the species level but fail to provide sufficient
ferent pubescent types and to maintain consistency basis for recognition at the generic level (Lorence,
with taxonomic concepts in Mexican and Central 1991).
American Arachnothryx, Williams's variety is here Subsequently, Borhidi (1997a, 1997b) trans¬
elevated to the species level as A. armentalis, the ferred to Javorkaea six Mesoamerican species, two
earliest available epithet. Furthermore, A. ovanden¬ from Rondeletia and four that he had previously
sis is here proposed as a synonym of A. armentalis. placed in Arachnothryx: A. chaeonii (Lorence) Bor¬
This species is closely related to A. buddleioides hidi |as chaconis], A. macrocalyx (Standley & Stey¬
(Bentham) Planchon, which differs in having leaves ermark) Borhidi, R. megalantha Lorence, R. scabra
Volume 15, Number 3 Lorence 451
2005 Mesoamerican Rondeletieae
Hemsley, A. torre.si/ (Standley) Borhidi, and A. Based on its pentamerous flowers and corolla with
itxpanapensis (Lorence & Castillo-Campos) Borhidi. internally densely yellow-barbate lobes and throat
These species all display relatively large white or Rondeletia standleyana clearly belongs to Rogiera
yellow corollas, puberulent around the mouth of the (see generic key above), not Arachnothryx to which
tube and Basally on the lobes within, but are not Borhidi (1987) incorrectly assigned it. Rogiera stan¬
otherwise closely related to Arachnothryx lumdu- dleyana is closely related to R. nicaraguertsis (Oer¬
rensis except lor their large flowers, which may rep¬ sted) Borhidi, which differs by its leaves with the
resent an adaptation for moth pollination. Recently, lamina adaxially hirtellous-pilosulous and abaxially
Borhidi (2003) described a new species, Javorkaea strigillo.se and stipules 4—5 mm long, in contrast to
pulcherrima Borhidi, from Chiapas, Mexico. Based being villous on both surfaces and w ith stipules only
on an examination of the isotype (Heath & hmg 1—3 mm long in R. standleyana.
881, PTBG) this last species name is clearly syn¬
Acknowledgments. Thanks are extended to Anna
onymous with Arachnothryx jurgensenii (Hemsley)
Stone for skillfully drawing the botanical illustration.
Borhidi. The addition of these seven species radi¬
Roy Gereau (MO) for kindly supplying the Latin di¬
cally changes the original circumscription of Javorkaea
agnosis. Charlotte Taylor (MO) for constructive com¬
sensu Standley’s section Hondurenses, rendering it
ments on the manuscript, and the curators of tin*
a heterogeneous assemblage of large-flowered
herbaria cited herein for access to their collections.
shrubs or small trees differing in no consistent
character or suite of characters from the majority
Literature Cited
of species otherwise placed in Arachnothryx.
The primary characters used to differentiate Ja¬ Borhidi, A. 1982. Studies in Rondeletieae (Rubiaceae) III.
The genera Rogiera and Arachnothryx. Acta Bot. Hung.
vorkaea, i.e.. tin* relatively long stipular sheath and
28: 65-71.
calyx cup, 1- to 3-aristate stipules, zygomorphie ca¬
-. 1987. Studies in Rondeletieae (Rubiaceae) X.
lyx, large corolla with basally puberulent lobes New combinations ol Central American taxa. Acta Bot.
within, and oblong hypanthium and capsule (Bor¬ Hung. 33: 301-303.
hidi, 2003), occur in various combinations in other -. 1997a. Studies in Rondeletieae (Rubiaceae),
XIII. New combinations of Mexican and Central Amer¬
species of Arachnothryx, thus representing ex¬
ican plants. Acta Bot. Hung. 40(1—4): 15—16.
tremes in a continuum of variation rather than
-. 1997b. Two new1 species of the genus Javorkaea
unique discrete character states. For these reasons, Borhidi et J. Komlodi (Rubiaceae). Acta Bot. Hung
Javorkaea is here considered as a synonym of Ar¬ 40(1-4): 17-20.
achnothryx and the necessary combination is made -. 2001. Additions and corrections In the "Nomen-
clator of Mexican and Central American Rubiaceae” of
below for R. megalantha. Borhidi (2004: 101) sim¬
I). H. Lorence. Acta Bot. Hung. 43: 37—78.
ilarly conceded that it was not possible to maintain -. 2003. Kspeeies nuevas de los generos Arach¬
Javorkaea and transferred Rondeletia scabra Hems¬ nothryx y Javorkaea (Rubiaceae, Rondeletieae) en la
ley (Javorkaea scabra (Hemsley) Borhidi) to Arach¬ flora de Mexico. Acta Bot. Hung. 45: 1 — 11.
-. 2004. El Rondeletia complejo en Mexico. Acta
nothryx.
Bot. Hung. 46: 91—135.
f. Arachnothryx megalantha (Lorence) Lor¬ -& M. Fernandez Zequeira. 1981. Studies in Ron¬
deletieae (Rubiaceae) 1. A new genus: Roige.Ua. Acta
ence, comb. nov. Basionym: Rondeletia me¬
Bot. Hung. 27: 309-312.
galantha Lorence, Novon 4: 132. 1994. Ja¬ -& M. Jarai-komlodi. 1983. Studies in Rondele¬
vorkaea megalantha (Lorence) Borhidi, Acta tieae (Rubiaceae). IV. A new' genus: Javorkaea. Acta
Bot. Hung. 40: 16. 1996-1997. TYPE: Hon¬ Bot. Hung. 29: 13-27.
Kiehn, M. 1995. Chromosome survey ol the Rubiaceae.
duras. Cuyamel. 23 Aug. 1924, M. A. Carleton
Ann. Missouri Bot. Card. 82: 398—108.
653 (holotype, US 1208409; isotype, US).
Lorence, D. H. 1991. New species and combinations in
See the discussion under Arachnothryx hondu- Mexican and Central American Rondeletia (Rubiaceae).
rensis, above. Novon 1: 135—157.
Mabberley, I). J. 1997. The Plant-Book: A Portable Dic¬
5. Rogiera standleyana (A. R. Molina) Lorence, tionary of the Vascular Plants, 2nd ed. Cambridge Univ.
Press, Cambridge.
comb. nov. Basionym: Rondeletia standleyana
Rova, J. E., P. Delprete, L. Andersson & V. A. Albert.
A. R. Molina, Ceiba 1: 262. 1951. Arachnoth¬ 2002. A irnL-F cpDNA sequence study on the Conda-
ryx standleyana (A. R. Molina) Borhidi, Acta mineeae—Rondeletieae—Sipaneeae complex with impli¬
Bot. Hung. 33: 302. 1987. TYPE: Honduras. cations on the phylogeny of the Rubiaceae. Amer. J.
Bot. 89: 145-159.
Morazan, in pine forest above Zambrano, 1200
Standley, P. C. 1918. Rubiaceae. In North American Flora
m, 20 July 1949, L 0. Williams & .4. Molina
32: 1-86.
R. 14417 (holotype, EAP not seen; isotypes, F, Williams, L. 0. 1973. Tropical American Plants. X1 \. Ron-
US [2]). deletiae Centro-americanae. Phytologia 26: 127—130.