Wurmbea (Colchicaceae, Anguillarieae) in Mpumalanga Province, South Africa, including the description of two new species *
Author
Oosthuizen, D.
Author
Balkwill, K.
text
South African Journal of Botany
2019
2019-12-31
127
117
123
http://dx.doi.org/10.1016/j.sajb.2019.08.050
journal article
10.1016/j.sajb.2019.08.050
1727-9321
10496719
2.
Wurmbea viridiflora
D. Oosthuizen & K. Balkwill
,
sp. nov.
Type:
South Africa
.
Mpumalanga
,
Lydenburg
(2530):
22 km
east of
Roossenekal
, De Berg mountain, in
Road Reserve
near junction of R577 and D238+,
2231 m
(–AA),
1 Mar 2017
,
Oosthuizen, Balkwill & Kirkel
2463
(
J
,
holo
.;
BMLH
,
LYD
,
K
,
PRE
iso
.).
Summer growing geophyte up to
320 mm
high when in bloom and
350 mm
when in fruit.
Corm
oblong ovoid,
10–15 mm
×
5–10 mm
. with brown tunics, produced into a narrow submembraneous flimsy neck,
10–25 mm
long.
Stem
green sometimes light brownish red just above the tunics,
50–180 mm
long from the corm to the upper leaf, 1.0–
1.5 mm
in diam.
Leaves,
green, alternating up the stem.
Basal leaf
solitary, usually erect and somewhat flexuous, green, narrowly linear, 100–300 ×
2–4 mm
, indistinctly many-veined; apex long attenuate; margin mostly involute to make leaves appear subterete, sometimes flat, entire; base broad, sheathing.
Cauline leaves
2, usually erect and somewhat flexuous, indistinctly many-veined; apex attenuate; margin involute to make leaves appear subterete, entire; lower cauline leaf inserted about the middle of the stem,
100–220 mm
long, with sheath portion
10–40 mm
long; upper cauline leaf inserted
10–25 mm
below the flowering spike and up to
60 mm
below the fruiting spike,
30–100 mm
long with sheathing portion
15–40 mm
long.
In
fl
orescence
spicate, 3–10-flowered;
peduncle
10–40 mm
long in bloom and up to
65 mm
long in fruit; rachis
15–60 mm
long in bloom and up to
90 mm
long in fruit, somewhat stout with flowers spaced
2–6 mm
apart and fruit up to
15 mm
apart, the indeterminate axis often somewhat flexuous and zig-zag in fruit.
Perianth
:
5
–
6 mm
long; tepals 6, stellately spreading, each with 3 veins running from the tip to the base; tube greenish-cream without, cream within, broadly cylindrical gradually widening upwards, 1–2 × 1.5–3.0 mm broad; lobes strongly clawed, diverging,
3–4 mm
long; claws cream flushed light greenish cream without, cream within; limbs cream sometimes flushed light greenish cream, margins sometimes involute.
Nectary
a distinctly raised area largely distal to the point of attachment of the filament, with a gradually declining distal face and a central,
1 mm
long, parallel-sided groove in which the filament rests, the inner faces of the proximal ends of the groove touch the filament, indistinctly lighter cream.
Filaments
white, straight, free section about
2 mm
long; anthers violet brown on young flowers turning golden yellow to brownish yellow on older ones, dorsifixed near the base, rounded-oblong; thecae 0.6 ×
0.2 mm
.
Pistil
ovary green, rarely with a purple tinge, oblong-elliptic,
4–5 mm
long; styles 3, light creamish-green, conical, subulate,
3–4 mm
long; stigmas suberect to erect, small, capitate.
Capsule
oblong to oblong-ovoid, 3- angled, 8–15 ×
3–4 mm
, about twice as long as perianth remains.
Seeds
rhomboid with rounded corners, 0.7 ×
0.8 mm
, slightly compressed, brown with a finely reticulate and shiny surface.
Figs. 2
,
3
,
4
.
Fig. 4.
Map of Mpumalanga, showing known sites for
Wurmbea burrowsii
●,
W. viridi
fl
ora
■ and
W. kraussii
▲.
Etymology:
The epithet viridiflora refers to the greenish cream flowers without blotches.
Diagnostic characters:
Wurmbea viridi
fl
ora
is similar to
W. burrowsii
and especially
W. angustifolia
,
but differs from both and from
W. elatior
in that the flowers are uniformly greenish-cream (
Fig. 2C
) and do not have the purple bilobed patch distal to the filament on the tepals. Neither
W. viridi
fl
ora
nor
W. burrowsii
have the numerous minute dots or bigger rounded oblong flecks that are usually present on the tepals of
W. angustifolia
. The tepals of
W. viridi
fl
ora
and
W. burrowsii
have more prominent claws than those of
W. angustifolia
and
W. elatior
.
Wurmbea viridi
fl
ora
is similar to
W. angustifolia
in stem height, the length of the leaves and number of flowers on the spikes, but the internodal distances between flowers is shorter in
W. viridi
fl
ora
and the pistil of
W. viridi
fl
ora
is nearly twice as long as that of
W. angustifolia
.
In addition,
W. viridi
fl
ora
has a nectary with a central groove that touches the filament at the base and has a smooth surface, rather than a nectary with a central pocket that is separated from the filament at the proximal end and has a minutely papillate surface as in
W. angustifolia
.
Distribution & ecology:
This taxon is currently known from only two localities in the Steenkampsberg, about
22 km
east of Roossenekal (
Fig. 4
). The vegetation
type
is Lydenburg Montane Grassland (Gm 18) (
Mucina and Rutherford, 2006
), where
W. viridi
fl
ora
grows in seasonal wetlands or seeps with either sandy soil over a sandstone substrate or humus rich loam at
2230–2250 m
(
Fig. 2A
). It shares these habitats with mosses, sedges and moisture-loving grasses.
Phenology:
Flowering specimens have been collected from January through to March.
Conservation notes:
The two localities are about
3 km
apart, giving an area of occupancy and an extent of occurrence of less than
3 km
2
. We estimate the populations to comprise about 400 plants. Additional surveys are required to establish if these are the only populations or whether the species occurs in the nearby Verloren Vallei Nature Reserve that is at slightly lower altitude. At one locality there is encroachment by
Acacia mearnsii
De Wild
(black wattle) and cattle are free to graze the other. We thus propose a provisional threat status of Vulnerable D1, 2 (
IUCN, 2012
).
3.4. Additional specimens seen
South Africa
.
MPUMALANGA
:
2530 (Lydenburg):
Mashishing District, Steenkampsberg, on turnoff to Nederhorst, near the junction of R577 and D238+ roads,
2231 m
(
−
AA),
01 Mar 2017
,
Balkwill, Oosthuizen & Kirkel 13,972
(E,
J
,
K
); On the farm De Berg 71JT,
2240 m
(
−
AA),
18 Jan 2018
,
Oosthuizen & Balkwill 2905
(BMLH,
J
,
LYD
);
Balkwill & Oosthuizen 14,149
(
J
).