Three new taxa and two noteworthy species of Peliosanthes (Asparagaceae, Convallarioideae) from Laos and Vietnam
Author
Averyanov, Leonid V.
0000-0001-8031-2925
Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Str., 2, 197376 St. Petersburg, Russia & av _ leonid @ mail. ru; https: // orcid. org / 0000 - 0001 - 8031 - 2925
av_leonid@mail.ru
Author
Nguyen, Van Canh
0000-0001-9578-0342
Institute of Applied Technology, Thu Dau Mot University, No. 6, Tran Van On Street, Phu Hoa Ward, Thu Dau Mot City, Binh Duong Province, Vietnam & nguyenvancanh @ tdmu. edu. vn; https: // orcid. org / 0000 - 0001 - 9578 - 0342
nguyenvancanh@tdmu.edu.vn
Author
Tanaka, Noriyuki
0000-0003-4437-2909
Hachioji-shi, Tokyo, 192 - 0352, Japan & sylvaasiaticae @ gmail. com; https: // orcid. org / 0000 - 0003 - 4437 - 2909
sylvaasiaticae@gmail.com
Author
Nguyen, Khang Sinh
0000-0001-5171-4140
Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, 18, Hoang Quoc Viet Road, Cau Giay, Hanoi, Vietnam; Graduate University of Science and Technology, Vietnam Academy of Science and Technology. Vietnam & nskhang @ gmail. com; https: // orcid. org / 0000 - 0001 - 5171 - 4140
nskhang@gmail.com
Author
Maisak, Tatiana V.
0000-0001-5919-6755
Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Str., 2, 197376 St. Petersburg, Russia & tmaisak @ mail. ru; https: // orcid. org / 0000 - 0001 - 5919 - 6755
tmaisak@mail.ru
text
Phytotaxa
2023
2023-08-24
609
3
209
221
http://dx.doi.org/10.11646/phytotaxa.609.3.4
journal article
10.11646/phytotaxa.609.3.4
1179-3163
8281388
Peliosanthes virescens
Aver., V.C.Nguyen, N.Tanaka & K.S.Nguyen
,
sp. nov.
(
Fig. 4
)
Diagnosis:
—Most similar to
P. argenteostriata
, but differs mainly by the rhizome with subterranean stolons, non-striated leaf blades, narrowly open spherical flowers, incurved, apically rounded, largely imbricate greenish white perianth segments, a nearly flat pale green staminal corona, and a broadly conic, three-ridged, greenish white pistil.
Type:
—
VIETNAM
.
Dak Lak Province
:
Ea’Hleo District
,
Ea’Hiao Village
, evergreen forest at an elevation of about
900 m
a.s.l.
,
1 February 2023
,
V
.
C
.
Nguyen
s.n.
, type herbarium specimens prepared from cultivated plants,
18 February 2023
,
V
.
C
. Nguyen,
L
. Averyanov,
AL 2037
.
Holotype
LE
:
LE01170311
(https://en.herbariumle.ru/?t=occ&id=166030). Isotype
LE
:
LE01170312
(https:// en.herbariumle.ru/?t=occ&id=166038). Photos of the cultivated plants used for preparing the type specimen—
LE
:
LE01123812
(https://en.herbariumle.ru/?t=occ&id=165101).
Etymology:
—The specific epithet refers to the greenish flowers.
Description:—Herb
terrestrial, rhizomatous, acaulescent, evergreen perennial.
Rhizome
clumpy or tuberous, 0.5– 1(1.5) cm long, (4)5–6(7) mm in diameter, covered with few remnants of papyraceous, whitish bracts, producing whitish subterranean stolons becoming over
10 cm
long.
Roots
several, rigid, fleshy, orange brown.
Stem
ascending or erect,
1–1.5 cm
high, covered with few remnants of whitish herbaceous bracts.
Leaves
distinctly petiolate; petiole rigid, usually suberect or slightly curved, (8)10–14(16) cm long; leaf blade narrowly ovate to elliptic, (7)8–12(13) cm long, (2)2.5–4.5(5) cm wide, somewhat rugose, leathery, glabrous, glossy, dark green above, light green beneath, shortly acuminate, with many longitudinal veins; secondary transverse veinlets numerous, indistinct, nearly perpendicular to longitudinal veins.
Flowering stem
(peduncle and inflorescence rachis) erect, much shorter than leaves, (5.5)6–7(7.5) cm long; peduncle (2.6)2.8–3.8(4) cm long,
1.8–2.2 mm
in diameter, stout, light green, bracteate; sterile bracts on peduncle (1)2–3(4), broadly triangular, acuminate, clasping, papyraceous-membranous, whitish, (7)8–1.2(1.4) cm long, (4)6–8(10) mm wide; rachis (1)1.5–2.5(3) cm long, bearing (4)6–8(10) flowers in raceme.
Floral bracts
2 (outer bract and inner bracteole) at base of pedicel, whitish, papyraceous-membranous, narrowly triangular, tapering to acute apex; bract borne below flower, (4)5–7(8) mm long, (1.2)1.4–2(2.2) mm wide; bracteole borne crosswise to bract, twice smaller.
Pedicel
ascending, cylindric,
1.6–2.2 mm
long, light green.
Flowers
blooming acropetally, solitary in axils of bracts, subsessile, nearly horizontal, spherical, narrowly open, (5)5.5–6(6.5) mm high, (6.5)7.5–8(8.5) mm wide, light greenish.
Perianth
distally 6-cleft; tube broadly bowl-shaped,
1–1.2 mm
high,
4.5–5 mm
in diameter; segments
6 in
2 whorls of 3, imbricate except distal portion, incurved, broadly ovate or almost circular, with rounded and scarcely recurved apex, abaxially convex, hyaline along margins, fleshy; outer 3 segments
5.5–6 mm
long,
4.5–5 mm
wide; inner ones
4.5–5 mm
long,
4–4.2 mm
wide.
Corona
nearly flat to slightly raised centrally (distally), less than
0.5 mm
high, hexagonal at base, (4.4)4.6–5(5.2) mm in diameter, inside below each anther obtusely thickened longitudinally, apical opening almost circular,
2–2.2 mm
in diameter.
Anthers
6, sessile, introrse, nearly circular,
0.5–0.6 mm
long and wide, light beige; pollen cream white.
Pistil
half-inferior, distal free part broadly conic,
1.4–1.6 mm
high,
2.8–3 mm
across at base, with 3 low longitudinal ridges decurrent from stigmatic lobes, pale greenish white; ovary hexagonal or stellate at base, internally incompletely 3-septate, each locule containing 4(6) ovules on central basal placentae; stigma 3-dissected, lobes narrowly obovate, tri-radially spreading,
0.2–0.3 mm
long.
Fruits
unknown.
Ecology and phenology:
—Occurs in primary or aged secondary submontane evergreen broad-leaved forests at an elevation of about
900 m
a.s.l. Flowers in February–March.
Conservation status:
—
Only a few mature individuals of this species were found in the
type
locality. For lack of sufficient data on the occurrence, we estimate the conservation status of the new species as “Data Deficient” (
DD
), following the guidelines of
IUCN (2022)
.
Distribution:
—
Vietnam
,
Dak Lak Province
(Ea’Hleo District). Currently known only from the
type
locality.
Taxonomic relationships:
—In having comparatively small habit, small leathery glossy somewhat rugose leaf blades (6–13 ×
2–5 cm
) and a short inflorescence (rachis
1–3 cm
long) with subsessile flowers (pedicels up to
2.2 mm
long),
Peliosanthes virescens
is morphologically close to
P. argenteostriata
,
P. convallarioides
and
P. nivea
. These four species are confined in distribution to central
Vietnam
and
Laos
. Unlike
P. virescens
,
P. argenteostriata
and
P. convallarioides
,
Peliosanthes nivea
is unique within these four species in having different coloration of adaxial (dark purple) and abaxial (white to greenish white) sides of perianth segments. Then,
P. virescens
is closer to
P. argenteostriata
than to
P. convallarioides
in having apically rounded segments, since the latter has more acute outer perianth segments. In addition,
P. virescens
is distinguishable from these three species by having subterranean stolons, narrowly open spherical greenish white flowers, incurved, apically rounded perianth segments, a nearly flat (or only slightly convex) greenish white staminal corona, and a broadly conic (or trihedral) three-ridged greenish white pistil.