Three new species and one new subspecies of Euryops (Asteraceae: Senecioneae) from the Klein Karoo in the Western Cape Province, South Africa.
Author
Vlok, J. H. J.
text
South African Journal of Botany
2020
2020-09-30
133
167
173
http://dx.doi.org/10.1016/j.sajb.2020.07.025
journal article
286104
10.1016/j.sajb.2020.07.025
108593c9-fd23-4fa7-80b2-61df903bb150
1727-9321
10496796
3.4.
Euryops subcarnosus DC. subsp. fallax J.H.J.Vlok
,
subsp.
nov.
Type:
South Africa
,
Western Cape Province
, Ladimsith (3320): about
30 km
along road to Laingsburg, just west of entrance to farm Van Zylsdamme, (-BD),
430 m
,
4 May 2004
,
J. Vlok
2839
(
NBG
, holo.)
.
Virgate, sparsely branched shrub, up to
1.2 m
tall; young branches tinged reddish, leafy, older branches (>2 years old) leafless.
Leaves
erect with tips spreading, 3—5 x ca.
1 mm
, terete, obtuse, subcarnose, glabrous, with small woolly tuft in axil, glaucus-green.
Peduncles
lateral in upper leaf axils,
25—40 mm
long, terete, ca.
1 mm
thick.
Involucre
widely cup-shaped,
6—8 mm
diam.
Involucral bracts
uniseriate, 6 or 7, glabrous, connate for ca. quarter of their length, triangular, 5—6 X
3 mm
, 5- to 7-veined, purplish in upper half, acute-penicillate.
Ray
fl
orets
6 or 7; corolla yellow, tube cylindrical,
2 mm
long, lamina oblong, 6 X
3 mm
, 4-veined; style branches erect, spreading, ca.
1 mm
long.
Disc
fl
orets
30—35; corolla yellow,
4—5 mm
long; tube cylindrical,
2 mm
long; limb campanulate,
2—3 mm
long, lobes triangular-acute with tip somewhat gibbous.
Anthers
2 mm
long with ovate appendage.
Style
terete, branches erect, ca.
0.5 mm
long, truncate, with densely papillate tip.
Pappus
bristles white, numerous,
2 mm
long.
Cypselas
5—6 X
3—4 mm
, densely lanate with white hairs that are not mucilaginous when wet. (
Plate 4
).
Flowering period
: May to July. Populations flower prolifically, but seemingly only for a period of two weeks.
Distribution and ecology:
Euryops subcarnosus
subsp.
fallax
is known only from the Ladismith district where it occurs in Succulent Karoo vegetation, more specifically in the Western Little Karoo unit
sensu
Mucina and Rutherford (2006)
. At a finer scale
Vlok and Schutte-Vlok (2015)
described this vegetation as Apronveld.
Diagnosis:
Euryops subcarnosus
subsp.
fallax
differs from the current four subspecies in having a unique combination of characters. It differs from the two subspecies with entire leaves in having shorter leaves (
5 mm
long vs
10—50 mm
long in
subsp.
subcarnosus
and
15—40 mm
long in
subsp.
foetidus
) and in lacking an apiculus (small white apiculus in
subsp.
subcarnosus
and pungent leaves with mucronate apiculus in
subsp.
foetidus
). It also differs from these two subspecies in the hairs of the achenes that do not become mucilaginous when moistened (vs. mucilaginous when wet in
subsp.
subcarnosus
and
subsp.
foetidus
). It differs from the two other subspecies (
subsp.
minor
and
subsp.
vulgaris
) in having entire and not lobed leaves. It may be unique in this species complex in having functionally male disc florets, but fruiting material from more populations needs to be investigated to confirm this observation.
Fig. 3.
Distribution of
Euryops dasyphyllus
(Z),
E. bertilii
(
*
),
E. diosmiphyllus
(
Δ
) and
E. subcarnosus
subsp.
fallax
(•). Graphics: A. Schutte-Vlok.
Euryops subcarnosus
is the most widespread and variable of the South African
Euryops
species
(
Nordenstam, 1968
), with
E. subcarnosus
subsp.
subcarnosus
the only subspecies previously known to occur in the Klein Karoo. No specimens intermediate between
E. subcarnosus
subsp.
subcarnosus
and
E. subcarnosus
subsp.
fallax
are known and the latter may warrant specific recognition, but with the current wide concept of the species, I regard it more prudent to treat this taxon as a subspecies.
Plate 1.
Euryops dasyphyllus
,
specimen
from the
type
locality.
Photo
:
A
.
Schutte-Vlok
.
Plate 2.
Euryops bertilii
,
typical plant at
type
locality. Photo:
J
. Vlok
.
Plate 3.
Euryops diosmiphyllus
,
typical plant at
type
locality. Photo:
J
. Vlok
.
Conservation notes:
Plants are locally abundant, but currently known from only three localities (
Fig. 3
). At the
type
locality plants occur only along the fenced road reserve, with no plants within the adjacent grazed camp. From the other two localities it is also clear that the plants are highly palatable to domestic stock and game. These observations suggest that the known populations have been severely reduced due to grazing. Following
Raimondo et al. (2009)
I
propose a conservation status of Endangered (
B2
(a) & (b)) for this subspecies
.
Etymology: The subspecies name (fallax) alludes to the fact that this taxon has been overlooked until now.
3.4.1. Additional material examined
South Africa
.
WESTERN CAPE
. 3320 (Ladismith):
Anysberg Nature Reserve
, about
1.2 km
west of
Goedehoop
house, (-
BC
)
,
9 July 2006
,
Vlok
&
Schutte
555
(
NBG
)
;
Anysberg Nature Reserve
, about
2 km
west of
Goedehoop
house,
14 July 2007
,
Vlok
&
Schutte
606
(
NBG
,
S
)
.
3.4.2. Changes to species key
This subspecies can be accommodated in the existing key to the subspecies of
Euryops subcarnosus
(
Nordenstam, 1968: 196
)
by changing couplet 2 to the following:
(i) Leaves
3—5 mm
long, lacking an apiculus.. ... ... ... ... ... ... ... ......
subsp.
fallax
(ii) Leaves>
10 mm
long, with small white or pungent mucronate apiculus.. ... ... ... ..... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... continue with existing key.