Studies in Neotropical Apocynaceae LIV: a synopsis of Asketanthera
Author
Morales, J. Francisco
text
Candollea
2018
2018-03-27
73
1
7
17
journal article
3533
10.15553/c2018v731a2
ea73ea53-7e6c-4e4e-8260-7da383dffc67
2235-3658
5683677
2.
Asketanthera dolichopetala
(Urb.) Woodson
in Ann.
Missouri
Bot. Gard. 19: 47. 1932 (
Fig. 2
,
3
).
Ξ
Echites dolichopetalus
Urb., Symb. Antill.
7: 335. 1912.
Lectotypus
(designated here):
DOMINICAN REPUBLIC
.
Prov. Barahona
:
near
Barahona
,
road to El Marisal
,
VII.1910
, fl.,
Fuertes
453
(
S
[
S04-1835
]!; isolecto
-
:
BM
!,
K
[
K000582733
]!,
L
[
L0004431
]!,
MO
[MO100108]!).
Branchlets
moderately to densely puberulent; interpetiolar colleters up to
1.1 mm
long.
Petioles
12-20 mm
long; leaf blades 5.8-10.3 ×
3.8-6.2 cm
, ovate-elliptic to elliptic, the apex acuminate, the base broadly acute to abruptly attenuate, very sparsely strigulose to hirsutulous on both surfaces, secondary veins slightly impressed abaxially, not visible adaxially.
Inflorescence
densely to moderately puberulent, 8-13-flowered, peduncle (30-)
35-55 mm
long, pedicels
5-9 mm
long, bracts 7-15 ×
1.5-5 mm
, elliptic to linear-elliptic; sepals 12-18 ×
4-6.5 mm
, elliptic to ovate-elliptic, the apex narrowly acuminate, moderately to sparsely hirsutulos externally, the colleter irregularly erose at the apex.
Corolla
cream, densely hirsutulous externally, tube 15-21 ×
1.7-3.7 mm
, inflated around the stamens,
1.7-2 mm
diam. at the orifice; lobes 24-28 ×
5.5-7 mm
, obliquely obovate-elliptic; stamens inserted in the proximal half of the corolla tube, anthers
6.4-7 mm
long, the auricles rounded, style-head
1.5-1.9 mm
long; ovary
1.5-2 mm
long, glabrous; nectaries c. two-third the length of the ovary, each nectary entire.
Follicles
unknown.
Distribution, habitat and phenology
. – Endemic to
the Dominican
Republic, where it grows in wet forest, from
90-
600 m
. Flowers have been reported in July and December.
Conservation status
. – Only two populations from severely fragmented habitats are known for
A. dolichopetala
. Additional fieldwork might reveal that this species has a wider distribution, but based on the current collections and the reduced AOO (
8 km
2
),
A. dolichopetala
is provisionally assessed as “Critically Endangered” [CRB1ab(iii,iv) + B2ab(iii,iv)] following IUCN Red List Categories and Criteria (
IUCN, 2012
).
Notes
. –
Asketanthera dolichopetala
is separated from
A. calycosa
and
A. p
icardae by its petioles
12-20 mm
and inflorescences with long peduncles. Fruiting specimens show some resemblance to
A. picardae
, but the latter species has shorter peduncles (
4-15 mm
vs. (30-)
35-55 mm
). The
holotype
of
Echites dolichopetalus
was destroyed in
May 1943
during World War II. The duplicate at S is designated here as the
lectotype
because is the most complete preserved specimen.
Specimens examined. –
DOMINICAN REPUBLIC
.
Prov. Barahona
:
Sierra del Bahoruco, La Ciénaga, section La Filipina, cañada La Baliza
,
7.XII.2006
, fl.,
Clase
4333
(
CR
,
MO
).