A review of the Euphorbia schinzii-complex (Euphorbiaceae) in southern Africa
Author
Bruyns, Peter V.
Bolus Herbarium, University of Cape Town, 7701 Rondebosch, South Africa
peter.bruyns@uct.ac.za
Author
Klak, Cornelia
Bolus Herbarium, University of Cape Town, 7701 Rondebosch, South Africa
Author
Hanáček, Pavel
Department of Plant Biology, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czechia
text
Phytotaxa
2020
2020-03-19
436
3
201
221
http://dx.doi.org/10.11646/phytotaxa.436.3.1
journal article
10.11646/phytotaxa.436.3.1
1179-3163
13874448
8.
Euphorbia schinzii
Pax (1898: 739)
.
Type:—
SOUTH AFRICA
. Transvaal (
Mpumalanga
): Berea Ridge, Barberton, 3100’,
13 February 1891
,
Galpin 1297
(
lectotype
BOL
! designated by
Bruyns (2012: 228)
,
isolectotype
K
!).
Fig. 6
.
Discussion:
—In the protologue of
E. schinzii
,
Pax (1898)
cited
two specimens
,
Rehmann 4347
from Pretoria,
South Africa
(missing and not seen by N.E.
Brown (1915: 364)
either) and
Galpin 1297
(BOL!, K!) from Berea Ridge at Barberton,
South Africa
(±
300 km
east of Pretoria). Pax gave the branches as 3-angled, but that is certainly an error and the fourth angle must have been entirely hidden in the pressed specimens he saw. He also mentioned ‘
angulis lobatis podariis
’, i.e. branches angled with the tubercles projecting somewhat (‘lobed’). Since
Rehmann 4347
is missing,
Galpin 1297
was selected as the
lectotype
for
E. schinzii
by
Bruyns (2012)
. In
Galpin 1297
the branches were
150−175 mm
tall (‘6−8 inches’), the tubercles are fused into angles, the spines are subtended by stipular prickles ±
2 mm
long and the specimen was collected in flower in February. The relatively tall branches, continuous angles with decurrent but not continuous spine-shields, fairly prominent stipular prickles and sessile cyathia with ± sessile ovaries make it clear that
Galpin 1297
is the same species as the type of
E. complexa
. Other recent collections from Barberton (e.g.,
Kluge 2281
(NBG)) are also identical to
E. complexa
.
FIGURE 6.
Distribution of
Euphorbia schinzii
(inverted triangle
= subsp.
schinzii
,
circle
= subsp.
bechuanica
, upright triangle
= subsp.
schinzioides
).
Traditionally, small (mostly <
150 mm
tall), clump-forming members of this complex from around Pretoria (also westwards and northwards) have been referred to as
Euphorbia schinzii
. These have been taken as typical of
E. schinzii
(
White
et al
. 1941
)
, to the extent that
White
et al
. (1941: 745)
,
Fourie (1988: 91
, 92) and
Hargreaves (1994: 147)
all gave the ‘
Type
locality’ of
E. schinzii
as ‘Pretoria Distr.; hills near Pretoria’. These plants are variably, but often strongly rhizomatous (
White
et al
. 1941
: Fig. 835, 836, 838,
Hargreaves 1994: 153
). The tubercles are fused into ± continuous though somewhat sinuate angles along the branches (sinuate when viewed from the side), the spine-shields are decurrent below the spines for
4−6 mm
, stipular prickles are minute and the ovaries are ± sessile.
Since the name
E. schinzii
now applies to plants from Barberton which are identical to
E. complexa
,
E. complexa
is a synonym of
E. schinzii
. The plants from Pretoria (also westwards and northwards) are not identical to these and require a name. However, they are not always easily distinguishable from
subsp.
bechuanica
(see below). Since they are separated by only rather weak and variable features, all three are now included as subspecies under
E. schinzii
.
Three subspecies are recognized and may be separated as follows:
1. Plant forming a robust shrub 15–50 ×
15–200 cm
, branches 8–12(–20) mm thick, not rhizomatous, spines
6–18 mm
long............. ...............................................................................................................................................................................
subsp.
bechuanica
1. Plant forming a small clump 5–20(–30) ×
8–50 cm
, branches 6–12(–20) mm thick, often rhizomatous, spines 3–12(–17) mm long....................................................................................................................................................................................................2.
2. Stipular prickles
0.5–1 mm
long, spine-shields broad and usually blackish........................................................
subsp.
schinzioides
2. Stipular prickles
1.5–3 mm
long, spine-shields slender and usually grey....................................................................
subsp.
schinzii