A revision and one new species of Begonia L. (Begoniaceae, Cucurbitales) in Northeast India
Author
Camfield, Rebecca
Author
Hughes, Mark
text
European Journal of Taxonomy
2018
2018-01-19
396
1
116
journal article
22365
10.5852/ejt.2018.396
2b95a851-e1bf-4bdd-9cce-441ddc4135d2
3787049
Begonia palmata
var.
khasiana
(Irmsch.) Golding & Kareg.
Phytologia
54: 495 (
Golding & Karegeannes 1984
). –
Begonia laciniata
subsp.
khasiana
Irmsch.,
Mitteilungen
aus dem Institut für allgemeine Botanik in Hamburg
10: 529 (
Irmscher 1939
). –
Type
:
India
,
Meghalaya
, Khasia mountains,
Hooker & Thomson 10
(lecto-: E00265074, here designated).
Other material
INDIA
:
Arunachal-Pradesh
:
20 Oct. 2002
,
Hutchinson & Cox et al. 10081
(
E
).
Manipur
:
Meebold 6395
(syn
B
n.v.).
Meghalaya
: Khasi Hills, Cherrapunji,
15 Apr. 1952
,
Chand 5356
(
MICH
); ibid.,
15 Aug. 1952
,
Koelz 31101A
(
MICH
); Khasi Hills, Mawphlang,
8 Apr. 1954
,
Chand 7503
(
MICH
); Khasi Hills, Mawryngkneng,
18 Oct. 1951
,
Koelz 28876
(
MICH
); ibid.,
4 Sep. 1951
,
Koelz 28337
(
MICH
); Khasi Hills, Pynursla,
17 Aug. 1949
,
Koelz 23516
(
MICH
); Khasia,
Clarke 54285B
(syn
B
n.v.); ibid.,
Griffith 2560
(syn
B
n.v.); Khasia mountains,
Hooker & Thomson 10
(
BM
,
K
); Shillong,
2 Apr. 1965
,
Cox & Hutchinson 306
(
E
,
K
).
Description
Stem: red tomentose. Stipules:
10–27 mm
long, red tomentose. Leaves: petiole densely red tomentose; lamina ovate, upper surface with short red pubescence all over, denser on veins, underside red, red pubescence all over, denser on veins; several lobes, long, triangular, not curved; apex acuminate or acute.
Remarks
A very variable species which has a wide distribution throughout Eastern Asia and Indochina. The lobes on the leaf margin vary from elongate acuminate to shortly triangular. Young leaves have very dense hairs which become less dense as the leaf matures. The leaves can also bear markings (
Koelz 33555
) ranging from a few simple spots to larger bands of colour similar to
B. annulata
or
B. rex
, although the deeply lobed margin separates
B. palmata
from these two species. This species is also vegetatively very similar to
B. flaviflora
, which is distinguished by its smaller yellow flowers.
Begonia flaviflora
also has shorter stipules and the upper surface of the leaves are almost glabrous with a few sparse hairs on veins, unlike those of
B. palmata
which usually has bristles scattered all over leaf from sparse to very dense. The longest wing on the fruit is only
1 cm
long in
B. flaviflora
and has a crenate tip which is not seen on
B. palmata
.
Begonia palmata
forms a natural hybrid with
B. longifolia
where the two are growing together, known as
Begonia
×
chungii
(
Peng & Ku 2009
;
Morris 2011a
). This hybrid has baccate fruit with wings, and is intermediate in form between the two parents. The leaves are deltoid and lobed like
B. palmata
with red margin and centre, sometimes with light green spots between the red veins.
There are several infra-specific taxa under
B. palmata
.
Two are present in the study area, with the
type
variety being
far more common.
Begonia palmata
var.
khasiana
is distinct for having densely red villose stems, petioles and peduncles. The upper surface of the leaves is quite rough, and feels like sandpaper to the touch when dried, due to the short bristles about
200 µm
long, in
B. palmata
var.
palmata
the hairs are softer and
400–700 µm
long (
Irmscher 1939
).
There is potential for other varieties to be present in the study area, such as
B. palmata
var.
bowringiana
(Champ. ex Benth.) Golding & Kareg.
(
Golding & Karegeannes 1984
; basionym:
Bentham 1852
), which are recorded from nearby
Yunnan
. However, given the variation we see in
B. palmata
applying these names is extremely difficult, and may not be biologically meaningful.