Caxamarca, a new monotypic genus of Senecioneae (Asteraceae) from northern Peru

6 Pages·1999·3.9 MB·

by  A Sagástegui A.

Caxamarca, a New Monotypic Genus of Senecioneae (Asteraceae)
from Northern Peru
Michael 0. Dillon
Department of Botany, The Field Museum, Chicago, Illinois 60605-2496, U.S.A.
Abundio Sagdstegui Alva
Museo de Historia Natural, Universidad Antenor Orrego, Casilla 1001, Trujillo, Peru
Abstract. A new monotypic genus of Astera¬ maphroditi 80—160 (vulgo 80-130); corollae tubulosae lu-
ceae—Senecioneae, Caxamarca, is described from teae, 12-15 mm longae; limbus profunde quinquelobus.
Antherae basis sagittata; collum filamenti basi dilatatum.
northern Peru. The single herbaceous perennial
Styli rami apice conico pilis penicillum centrale. Achaen-
species, Caxamarca sanchezii M. 0. Dillon & Sa¬ ia decemcostata pilosus; pappi setae biseriate 6-7 mm
gdstegui, is endemic to the seasonally dry valleys longus barbellatae persistentes.
ol southwestern Cajamarca. The potential relation¬
ships of the genus are discussed.
Caxamarca sanchezii M. 0. Dillon & Sagdstegui,
RESUMEN. Un gdnero monotfpico nuevo de Aster¬ sp. nov. TYPE: Peru. Dept. Cajamarca: Prov.
aceae—Senecioneae, Caxamarca se describe para el Contumaza, Alrededor de San Benito, 1200 m,
norte de Peru. La unica especie, la herbacea per- 12 May 1994, A. Sagdstegui A., S. Leiva & C.
enne, Caxamarca sanchezii M. 0. Dillon et Sagas- Sagdstegui 15185 (holotype, HAO; isotypes,
tegui, es endemica de los valles estacionahnente CPUN, F, MO, US). Figures 1, 2.
secos del suroeste del Departamento de Cajamarca.
Perennial herbs to 1.5 m tall; roots fasciculate,
Se discuten las relaciones potenciales del genero.
tuberous, malodorous, individual tubers 8-12 cm
During continuing detailed studies on the flora long, 2—3 cm diam., white; stems fistulose, 1-2.5
of northern Peru, the following monotypic genus of cm diam. at the base, unbranched, glabrous,
Senecioneae (Asteraceae) was encountered in the winged by the decurrent leaf bases, the wings 4—7
seasonally dry river valleys in southwestern Caja¬ mm wide, glabrous, reticulate-nerved, denticulate,
marca. This new genus is proposed after an ex¬ ciliolate. Leaves basal and cauline; basal leaves ro-
haustive examination of all available genera within sulate, the blades profoundly dissected, odd pin¬
the tribe and detailed studies on many neotropical nate, the rachis 40—50 cm long, 8-10 pairs of leaf¬
members of the large and complex genus Senecio lets, the leaflets ovate to lanceolate, 5—10 cm long,
L. While generic concepts within the Senecioneae 2-6 cm wide, the margins dentate-serrate; cauline
have been reviewed (Barkley, 1985a; Barkley et al., leaves alternate, sessile, decurrent, the blades ob¬
1996; Bremer, 1994; Nordenstam, 1978), future long-lanceolate, 20-35 cm long, 7-11 cm wide,
changes are to be expected as taxonomies are tested membranous, apieally acuminate, the margins ir¬
with data from other disciplines, such as molecular regularly dentate-serrate, reticulate-nerved, gla¬
systematics. brous, the nerves sparsely pilose. Capitulescences
cymose-corymbose. Capitula 3—7(—20), radiate;
Caxamarca (Asteraceae tribe Senecioneae) M. 0. pedicels 1—8 cm long, striate, swollen apieally,
Dillon & Sagastegui, gen. nov. TYPE: Caxa¬ densely pilose; calyculus (10—)16-22-braeteolate,
marca sanchezii M. O. Dillon & Sagastegui. the bracts narrowly linear, 1-2 cm long, 0.5-1 mm
wide, acuminate apieally, 1-nerved, greenish pur¬
Herba rhizomatosa usque ad 1.5 m alta, radices carnosi
ple; involucres hemispherical, ca. 10 mm tall, ca.
foetidi; caules erecti simplexalata medullosus. Folia ba-
10 mm wide; phyllaries (17-)22-28, weakly bi¬
sale 40-50 cm longa, profunde pinnatisecta. Folia caulina
alterna, herbacea, sessilia, basi decurrentis; lamina plana seriate, equal, lanceolate, 8-10 mm long, 2-3 mm
herbacea 20—35 cm longa, 7—11 cm lata, margine distinc- wide, fused at the base, glabrous or pilose, acu¬
te denticulata. Capitulescentiae corymboso-cymosae 3-20 minate; ray florets 10—22, pistillate, the corolla yel¬
capitulis (vulgo 3—7). Capitula heterogama radiata ca. 10
low, the tube 0.5-0.6 mm long, glabrous, the ligule
mm alta, ca 10 mm lata; phyllaria subbiseriatis 17-28
(vulgo 22-28). Flores radiati pistillati 10-22: ligulae lu- oblong-linear, 10-25 mm long, 4—8 mm wide, gla¬
teae, 10-25 mm longae, 4-8 mm latae. Flores disci her- brous, 10—12-nerved, 2-3-dentate apieally; disc
Novon 9: 156-161. 1999.
Volume 9, Number 2 Dillon & Sagastegui 157
1999 Caxamarca from Peru
Figure 1. Caxamarca sanchezii VI. (). Dillon & Sagastegui. —A. Flowering branch. —B. Portion of basal leaf. —C.
Fleshy roots. —D. Capitulurn. —E. Involucre. —F. Ray floret. —G. Disc floret. —H. Corolla lobes. —1. Stamen. —J.
Style branches of disc floret. —k. Achene with pappus. —L. Enlargement of achene cross section. Illustration based
on Sagastegui, Leiva & Sagastegui 15185 (HAO).
158 Novon
Figure 2. Caxamarca sanchezii. —A. Basal leaves in greenhouse grown plant (scale in inches). —B. Flowering stem
photographed in the field. —C. Capitulescence.
florets 80-130(-160), hermaphroditic, the corollas anther bases sagittate, the filaments basal collar
yellow, tubular, 12-15 mm long, the throat slightly swollen or balusterform; style branches with par¬
expanded, deeply 5-lobed, the lobes oblong, 2-2.5 allel stigmatic lines, the apices conical with a ter¬
mm long, 0.8-1 mm wide, apically obtuse, reflexed; minal crown of penicillate trichomes. Achenes cy-
Volume 9, Number 2 Dillon & Sagastegui 159
1999 Caxamarca from Peru
lindrical, 2.5-4 mm long, 0.5—0.6 mm wide, growth, flowering, and fruiting are completed within
10-costate, densely pilose with biseriate trichomes; three months. After flowering, the stems die back
pappus biseriate, persistent, the bristles subequal, and leave little trace of their existence until the
barbellate, 6—7 mm long. next year. Some aspects of its auteeology are similar
to geophytes which begin their development with
Distribution and ecology. Caxamarca sanchezii the coming of the rainy season and flower after the
grows in clay soils in semi-arid open habitats with vegetative growth period.
scattered deciduous small trees and evergreen Etymology. The generic name is derived from
shrubs. It is confined to the adjacent cuencas or the original Spanish rendering of Cajamarca, the
drainage basins of the Rio Chicama and Rio Je-
native Quechua name for this area in northern
quetepeque (1200—2200 m) in southwestern De¬
Peru. It is a pleasure to dedicate this new species
partment of Cajamarca. These areas are a part ol to its first collector, Isidoro Sanchez Vega, the
the western or Pacific slope with the rivers draining founder and current director of the herbarium at
to the Pacific Ocean. The prevailing weather pat¬ Universidad Naeional de Cajamarca (CPUN).
tern, and hence available moisture, is associated
with coastal weather systems and unpredictable but Paratypes. PERU. Dept. Cajamarca: Prov. Contu-
recurrent El Nino conditions (Dillon & Rundel, maza, Travesfa de Andaloy (San Benito—Yeton), Sagdste-
1990). Flowering is between March and May in nor¬ gui & Leiva 15491 (F. HAO), Sagastegui & h-iva 15536
(F, HAO); S. 0. de El Rupe. Km 13 de la carretera Chi-
mal years.
lete-Contumaza. Sanchez 2243 (CPUN); Chilete-Rupe,
In favorable years, the associated floristic com¬ Sanchez 4219 (CPUN, HAO); Cushion (Chilete—Contu-
munity is dominated by several annual Poaceae maza), Sagastegui et al. 15628 (F, HAO), Sagastegui et
genera. Other species recorded from the collecting al. 15857 (F, HAO); Tambo Ua Eima (Cascas—Contumaza),
Sagastegui et al. 15548 (F, HAO); Prov. San Pablo, San
localities include Acacia angustissima (Miller)
Bernardino—Sangal, Sagastegui et al. 15597 (F, HAO).
Kuntze (Fabaceae), Caesalpinia paipai Ruiz & Pa-
von, C. spinosa (Molina) Kuntze (Fabaceae), Erio- Discussion. Our studies in the Andean Sene-
theca discolor (HBK) Robyns (Bombacaceae), Cor- cioneae (Dillon & Sagastegui, 1988, 1996; Vision
dia macrocephala (Desvaux) Kunth, C. munda I. M. & Dillon, 1996; Sagastegui & Dillon, 1985) have
Johnston (Boraginaceae), Solarium sp. (Solanaeeae), revealed rich generic and species diversity. With
Verbesina saubinetioides S. F. Blake (Asteraceae), this addition, Peru contains no fewer than 15 de¬
Zinnia peruviana (L.) L. (Asteraceae). The region scribed genera and over 320 species within the
also contains an association of several geophytes: tribe Senecioneae (Dillon & Hensold, 1993). This
Ismene amancaes (Ruiz & Pavon) Herbert (Amar- new genus belongs to the subtribe Senecioninae
yllidaceae), Leptochiton helianthus (Ravenna) Ger- Dumortier, diagnosed by a series ol microcharac¬
eau & Meerow (Amaryllidaceae), Stenomesson sp. ters, including balusterform anther collars and style
(Amaryllidaceae), and Trichlora peruviana Baker branches with separate stigmatic lines (Bremer,
(Liliaceae). 1994).
Phenology. The life history of Caxamarca in The combination of characters displayed by Cax¬
the seasonally dry valleys of southwestern Caja¬ amarca does not allow its placement within any
marca is closely connected with the yearly cycles described genus known to us within the Seneci¬
of rain and drought. In the region where it is en¬ oneae: the distinctive herbaceous perennial habit,
demic, the rainy season typically begins in late De¬ with enlarged fleshy or tuberous roots, precocious
cember and rainfall increases steadily until March. basal leaves (Fig. 2A), scapose fistulose stems with
By April the rains begin to decrease and by the decurrent cauline leaves (Fig. 2B). lax and few¬
end of May the area is completely dry once again. headed cymes, and large capitula with conspicuous
Rainfall between June and November is infrequent reflexed, bright yellow ray corollas (Fig. 2C). The
and of short duration. Soon after the rainy season style branches of the disc florets have parallel stig¬
begins, a series of long-petioled, basal leaves matic lines and convex to triangular apices with a
emerge sequentially, one every 4—5 days. Basal terminal crown of penicillate trichomes. This type
leaves are unknown from field-collected material of style apex is unlike those found in the large and
since they are extremely ephemeral, but were ob¬ diverse genus Senecio L.
served in cultivated plants (Fig. 2A). In nature, the Principal basal leaves and fibrous roots similar
basal leaves are completely absent in flowering in¬ to those present in Caxamarca are known from oth¬
dividuals; they develop and die hack to the ground er genera within the Senecioneae, for example, Pip-
prior to the development of the flowering stems. The penalia, a Mexican radiate genus once considered
flowering shoot develops rapidly, and vegetative intermediate between Cacalia and Senecio (Barkley,
160 Novon
1985b; Barkley et al., 1996). Some species of Se- ally rose to purple; anther collar filament
necio develop prominent basal leaves, for example, swollen or balusterform .
. Pseudogynoxys (Greenman) Cabrera
the Brazilian Senecio pulcher Hooker & Arnott. The
lb. Erect, herbaceous perennials; leaves basal, or
morphology of the basal leaves in Caxamarca is basal and cauline with long-decurrent petioles;
still an open question since basal leaves have not capitula radiate.
been collected in the field. While not common, 3a. Leaves strictly basal, no cauline leaves evi¬
fleshy roots with greatly thickened tubers do occur dent; capitulescence a long-scapose, solitary
capitulum .Dorobaea Cassini
in some Mexican Rolandas (T. Barkley, pers.
3b. Leaves basal and cauline; capitulescence
comm.) and in other tribes such as the Liabeae cymose-corymbose .
(e.g., Munnozia sagasteguii H. Robinson) occurring . Caxamarca M. O. Dillon & Sag&stegui
in this region.
Acknowledgments. We are grateful to the Univ-
In the key to genera provided by Vision and Dil¬
ersidad Privada Anterior Orrego for supporting field
lon (1996), Caxamarca would key to Dorobaea Cas¬
studies. Theodore Barkley is acknowledged for
sini. The large radiate hemispheric capitula with
valuable review comments, which greatly improved
well-developed calyculus and numerous phyllaries
the manuscript. We thank Fred Barrie and Nancy
are reminiscent of those found in Dorobaea, a small
Hensold for comments on an early version of the
Andean genus distributed in northern Peru, Ecua¬
manuscript. The illustration was prepared by Se-
dor, and southern Colombia (Nordenstam, 1978;
gundo Leiva Gonzales, Professor of Botany at
Nordenstam & Pruski, 1995). Dorobaea was estab¬
UPAO. Lastly, the authors wish to acknowledge and
lished as distinct from Senecio on character differ¬
thank Theodore Barkley, Harold Robinson, John
ences in the habit, capitulescences, and floral mor¬
Pruski, Bertil Nordenstam, and especially, the late
phology. The distinctness of the genus has been
Jos6 Cuatrecasas, for sharing their ideas concerning
confirmed by cpDNA variation studies (Kadereit &
generic concepts in the Senecioneae.
Jeffrey, 1996). Dorobaea has deeply lobed or pin¬
nate, basally rosulate leaves present at the time of
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