A revision of Solanum section Herpystichum
Author
Tepe, EJ
Department of Biology, 257 South 1400 East, University of Utah, Salt Lake City, Utah 84112, U. S. A.; Department of Biological Sciences, 614 Rieveschl Hall, University of Cincinnati, Cincinnati, Ohio 45221, U. S. A.
eric.tepe@gmail.com
Author
Bohs, L
Department of Biology, 257 South 1400 East, University of Utah, Salt Lake City, Utah 84112, U. S. A.
text
Systematic Botany
2011
2011-12-31
36
4
1068
1087
https://doi.org/10.1600/036364411X605074
journal article
10.1600/036364411X605074
2de37bc1-3782-435b-b655-0f9d77f7afe9
6327846
3.
SOLANUM DOLICHORHACHIS Bitter,
Repert.
Spec. Nov.
Regni Veg. 11: 490. 1913
.
—TYPE:
ECUADOR
.
Guayas
:
Balao
,
“in silvestris, rarium,”
May 1892
(fl, fr),
H. Eggers
14641
(
holotype
:
M–M0111203
!;
isotypes: A–GH00077619!, B [destroyed], L–L0403275!, LE [photo!],
US
–1324515!, WU!; photo of Bisotype [F neg. 2658]: G–G00080131!).
Scandent shrub or liana, climbing to
8 m
or more. Stems slender, wiry-woody, glabrous to moderately pubescent with trichomes
0.1–0.2 mm
long, these frequently in distinct lines along stem. Sympodial units plurifoliate. Leaves simple, the arrangement distichous, the blades 4.4–11 ×
1.3–4.5 cm
, 2–3 times as long as wide, ovate to elliptical, chartaceous to coriaceous to somewhat fleshy, glabrous to moderately pubescent on the midvein adaxially, glabrous abaxially; venation pinnate, with ca. 5 pairs of secondary veins, the veins sand-punctate; base oblique, sides of the lamina
3–4 mm
distant on the petiole, the two sides rounded to truncate to somewhat cordate; margins entire; apex acuminate; petioles
0.2–0.6 cm
, moderately pubescent adaxially, sandpunctate. Internodes
0.7–2.8 cm
. Inflorescences
3–55 cmlong
, unbranched, terminal to extra-axillary to nearly leaf-opposed, with 14–116 flowers (scars), the axes slender, densely pubescent; peduncle
2–5 cm
; rachis
2–49 cm
; pedicels
5–6 mm
in flower, slender,
13–14 mm
in fruit, glabrous to minutely pubescent, spaced
1.5–8 mm
apart. Calyx
1.5–2 mm
long, membranous, sparsely pubescent, sand-punctate, the tube ca.
1 mm
long, the lobes 0.5–1 × ca.
2 mm
, broadly rounded, rounded to shortly acuminate at tips; fruiting calyx not accrescent. Corolla
0.7–1 cmindiameter
,
3–5 mm
long, stellate, membranous, white to greenish-white, the lobes 3–4.5 ×
1.5–2 mm
, lanceolate, acute at tips, reflexed at maturity, glabrous adaxially, pubescent along center of petal abaxially, the margins ciliate. Stamens with filaments
0.5–1 mm
long, glabrous; anthers ca. 2.5 ×
1 mm
. Ovary glabrous; style 3–4 × ca.
0.3 mm
, clavate, glabrous; stigma capitate. Fruits (immature) 9–18 ×
4–6 cm
, 2–3 times as long as wide, spindle-shaped to possibly cordate, pointed at apex, the color unknown, glabrous. Seeds unknown.
Figure 2C
.
Habitat and Distribution—
Solanum dolichorhachis
occurs in the Pacific and Amazonian lowlands of
Ecuador
and in the Amazonian lowlands of
Peru
;
50–350 m
in elevation. (
Fig. 5
)
Phenology—
Flowering specimens have been collected in Apr. and Dec.; fruits have been collected in Apr.
Conservation Status—
According to the IUCN red list categories (
IUCN 2010
),
S. dolichorhachis
is classified as B1a+biii (critically endangered). This species is only known from five widely scattered locations, two of which are in western
Ecuador
, an area that continues to experience extreme habitat degradation (
Dodson and Gentry 1991
). The location at Limoncocha is in the center of an oil field, continued development of which is encroaching on all sides of the 4,600 ha Reserva Biológica Limoncocha (E. J. Tepe, pers. obs.). Despite its broad distribution, only five collections of this species are known, suggesting that it occurs at low densities, and appears to have been rare even at the time of collection. The label on the
type
specimen notes
in silvestris, rarium
(and
in silvis rarissimum
on some of the isotypes).
Solanum dolichorhachis
was collected near the Laguna de Limoncocha near the Río
Napo
in 1974 (
B. A. Drummond III 7329
, MO); however, EJT was unable to relocate this species during a five day visit to the Reserva Biológica Limoncocha in 2009.
Montúfar (2000)
listed
S. dolichorhachis
as a critically endangered species endemic to
Ecuador
. If the Peruvian collection is, in fact, a population of
S. dolichorhachis
(see below), then the species is more widespread than previously believed. Nevertheless, based on the number of collections available for this species, we believe that it is critically endangered, especially in western
Ecuador
where the
type
was collected and which has experienced tremendous habitat destruction.
Etymology—
The epithet
dolichorhachis
refers to the long, slender inflorescences of this species.
Notes—
Solanum dolichorhachis
is a climbing species recognizable by the long and slender inflorescences, small stellate flowers, spindle-shaped fruits, and the simple, usually large leaves with distinctly oblique bases. This species is most similar to
S. pacificum
, but the wiry-woody stems, densely shortpubescent inflorescences and young stems, and oblique leaf bases set this species apart.
The label from the
type
collection describes the fruits as cordate (
fructu cordato
). It is difficult to know what Eggers saw in three dimensions based on the single fruit on the isotype at A, but Egger’s notes suggest that the fruits may have been flattened and, therefore, possibly somewhat like those of the ground-trailing species in shape (i.e.
Figs. 1B–C
).
The collections of this species from eastern
Ecuador
differ somewhat from the
type
in that they have longer pubescence, darker stems that are densely sand-punctate (vs. light tan, non-punctate stems), inflorescences with less dense and coarser pubescence, and non-punctate calyces. The Peruvian collection is closer to the
type
in leaf shape than collections from eastern
Ecuador
, but the plant appears to be rather fleshy. It is possible that the two variants from the regions east of the Andes merit recognition at the species level; however, they have no unambiguous, qualitative differences and, since this species has been collected few times, there is currently insufficient material upon which to base further taxonomic decisions.
Additional Specimens Examined—
ECUADOR
.
Los Ríos
: Near Quevedo, Canton Vinces, Hacienda San José,
0°30’S
79°21’W
,
50 m
,
28 Oct 1934
(fl),
Y. Mexia 6617
(UC,
US
). Sucumbíos: Limoncocha on Río Napo,
0°23′15”S
76°36′35″W
,
300 m
,
1 Oct 1974
(fr),
B. A. Drummond III
(
MO
). Orellana: Parque Nacional Yasuni, Río Tiputini, al noroeste de al confluencia con el Río Tivacuno,
0°38’ S
76°30’ W
,
200–300 m
,
25 Apr 2002
(fl),
G. Villa et al. 1461
(BM, F).
PERU
.
Loreto
: Maynas, Indiana, Reserva Explorama,
3°28’S
72°50’W
,
106 m
,
9 May 1990
(fl),
R. Vásquez & N. Jaramillo 13680
(MO,
NY
).