Weberbauera arequipa (Brassicaceae), a New Species from Peru

Abstract

Weberbauera arequipa Al-Shehbaz & Mon-tesinos (Brassicaceae), a new species from Peru, is described and illustrated. It is distinguished from the other species of Weberbauera Gilg & Muschler by having ebracteate racemes, persistent sepals and petals, 4-seeded fruits, and a few simple trichomes restricted to the petiolar bases. It is closely related to the Bolivian W. retropila Al-Shehbaz, but differs by the lack of branched trichomes and by having glabrous fruits, smaller flowers, and persistent petals. The IUCN status of the new species is determined as Data Deficient (DD).

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Weberbauera arequipa (Brassicaceae), a New Species from
Peru
Author(s): Ihsan A. Al-Shehbaz and Daniel B. Montesinos
Source: Novon: A Journal for Botanical Nomenclature, 19(3):281-283. 2009.
Published By: Missouri Botanical Garden
DOI: 10.3417/2008075
URL: http://www.bioone.org/doi/full/10.3417/2008075
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Volume 19
Number 3
2009
NOVON
Weberbauera arequipa (Brassicaceae), a New Species from Peru
Ihsan A. Al-Shehbaz
Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri, U.S.A. 63166-0299.
ihsan.al-shehbaz@mobot.org
Daniel B. Montesinos
Universidad Cato
´lica de Santa Marı
´a, Arequipa, Peru. danielbotanico@gmail.com
ABSTRACT .Weberbauera arequipa Al-Shehbaz & Mon-
tesinos (Brassicaceae), a new species from Peru, is
described and illustrated. It is distinguished from the
other species of Weberbauera Gilg & Muschler by
having ebracteate racemes, persistent sepals and petals,
4-seeded fruits, and a few simple trichomes restricted to
the petiolarbases. It is closely related to the Bolivian W.
retropila Al-Shehbaz,but differs by the lack of branched
trichomes and by having glabrous fruits, smaller
flowers, and persistent petals. The IUCN status of the
new species is determined as Data Deficient (DD).
Key words: Brassicaceae, IUCN Red List, Peru,
Weberbauera.
Gilg and Muschler (1909) established Weberbauera
Gilg & Muschler (Brassicaceae) as a monotypic genus
based on a species they described from Peru as W.
densiflora Gilg & Muschler. Schulz (1924) recognized
two species in the genus and reduced the above to
synonymy of W. spathulifolia (A. Gray) O. E. Schulz.
Macbride (1934) expanded the limits of Weberbauera
by the transfer of the type species of two monospecific
genera, Alpaminia O. E. Schulz and Pelagatia O. E.
Schulz. Al-Shehbaz (1990a) further expanded the
genus by the discovery of five new species and by the
transfer of six previously placed in Stenodraba O. E.
Schulz. Several species have since been added to
Weberbauera (Al-Shehbaz, 1990b, 2004) and, as
presently stands, the genus consists of 23 species,
including the novelty below, W. arequipa Al-Shehbaz &
Montesinos. The new species was discovered during the
2005–2006 fieldwork in the Peruvian departments of
Arequipa and Moquegua by the second author (D.B.M.)
as part of his research toward the bachelor degree at
Universidad Cato
´lica de Santa Marı
´a, Arequipa.
Weberbauera arequipa Al-Shehbaz & Montesinos,
sp. nov. TYPE: Peru. Arequipa: Arequipa Prov.,
Distr. San Juan de Tarucani, Tico Tico, 16u069300S,
70u599160W, riverbed, 4181 m, 3 Apr. 2006, D. B.
Montesinos & L. P. Mondrago
´n 936 (holotype,
WAG; isotypes, MO, USM). Figure 1.
Herba annua ca. 6 cm alta, glabra. Folia caulina
oblanceolata, 8–12 33–5 mm, petiolata, dentata, petiolis
ad basim ciliata. Racemi ebracteati; pedicelli fructiferi
divaricati, 2–4(–5) mm longi, glabri, recti. Sepala oblonga,
1.1–1.3 30.6–0.8 mm, glabra; petala alba, anguste obovata,
1.8–2 30.7–0.9 mm; ovula 4. Fructus oblongus vel
lanceolatus, 5–7 31.3–1.6 mm, stylo 0.3–0.5 mm longo
coronatus; semina oblonga, uniseriata, 1.3–1.6 30.9–1 mm,
cotyledonibus incumbentibus.
Herbs annual, ca. 6 cm tall; trichomes absent
except a few simple ones at base of petioles; stems
decumbent, glabrous, several branched above base.
Cauline leaves oblanceolate, petiolate, 8–12 33–
5 mm, petioles 2–4 mm, blade glabrous, base atten-
uate, margin dentate. Racemes ebracteate, elongated
slightly in fruit; rachis straight. Sepals green, oblong,
1.1–1.3 30.6–0.8 mm, glabrous, membranous at
margin, not saccate at base; petals white, narrowly
obovate, 1.8–2 30.7–0.9 mm, not clawed; filaments
white, 1–1.5 mm; anthers ovate, ca. 0.4 mm; ovules 4
doi: 10.3417/2008075 NOVON 19: 281–283. PUBLISHED ON 11 SEPTEMBER 2009.

per ovary. Fruiting pedicels mostly divaricate, 2–4(–5)
mm, straight, slender; fruits oblong to lanceolate, 5–7
31.3–1.6 mm, not torulose, straight; valves with an
obscure midvein, glabrous; style 0.3–0.5 mm; stigma
entire. Seeds dark brown, oblong, uniseriate, 1.3–1.6
30.9–1 mm; cotyledons incumbent.
Distribution and IUCN Red List category. Weber-
bauera arequipa grows at riverbeds in grasslands,
together with Jarava ichu Ruiz & Pavo
´n, Werneria
pygmophylla S. F. Blake, Azorella compacta Philippi,
and Perezia multiflora Lessing. It is known thus far
only from the type locality and appears to be
extremely rare. However, its IUCN Red List category
(IUCN, 2001) is determined as Data Deficient (DD).
Etymology. The species epithet arequipa, named
after the Peruvian department and province Arequipa, is
a noun used in apposition and, therefore, should be
maintained according to Article 23.5 of the International
Code of Botanical Nomenclature (McNeill et al., 2006).
Discussion. The new species is readily distin-
guished from the other species of Weberbauera by its
ebracteate racemes, persistent sepals and petals, 4-
seeded fruits, and few simple trichomes restricted to
the petiolar bases. It is related to the Bolivian
endemic W. retropila Al-Shehbaz but differs by the
absence (vs. presence) of branched trichomes and by
having glabrous (vs. retrorsely pubescent), 4- (vs. 6 or
8)-seeded fruits, glabrous (vs. sparsely pubescent) leaf
Figure 1. Weberbauera arequipa Al-Shehbaz & Montesinos. —A. Fruiting plant. —B. Sepal. —C. Petal. —D. Fruit with
fruiting pedicel and persistent sepals and petals. Drawn from the holotype Montesinos & Mondrago
´n 936 (WAG).
282 Novon

surfaces, smaller flowers (sepals 1.1–1.3 mm vs. 2–
2.5 mm long, petals 1.8–2 mm vs. 3–3.5 mm long),
and persistent (vs. caducous) petals.
Acknowledgments. We are grateful to Victoria C.
Hollowell for the editorial advice and to anonymous
reviewers for their critical remarks on the manuscript.
We also thank Jan Wieringa (WAG) and Susana
Montesinos for help.
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Volume 19, Number 3 Al-Shehbaz & Montesinos 283
2009 Weberbauera (Brassicaceae) from Peru