A taxonomic revision of Schoenus cuspidatus and allies (Cyperaceae, tribe Schoeneae) - Part 2
Author
Elliott, T. L.
Author
Muasya, A. M.
text
South African Journal of Botany
2020
2020-05-31
130
327
347
http://dx.doi.org/10.1016/j.sajb.2019.12.015
journal article
10.1016/j.sajb.2019.12.015
1727-9321
10496754
8.
Schoenus riparius
T.L.Elliott & Muasya, S.
African J. Bot.
112: 359 (2017).
Tetraria paludosa
Levyns, J. S.
African Bot.
13: 85
—
87 (1947)
.
Type
:
South Africa
,
Western Cape Province
, 3318 (
Cape
Town
):
Camps Bay
, round edge of a marshy spot, (
—
CD),
28 Oct 1945
,
Levyns
7915
(BOL!, holo. [
BOL139430
]).
Tetraria cuspidata
(Rottb.) C.B.Clarke
f. robustior
K uk €., Repert. Spec. Nov. Regni.
Veg. 29: 187 (1931)
.
Type
:
South Africa
,
Western Cape Province
, 3419 (
Simonstown
):
Hout Bay
, (
—
AB),
10 Jan 1921
,
Pillans
4864
(BOL!, lecto. [
BOL5071
], here designated; K! [K000244907], iso.). [Note: K ukenthal € (1931) cited
two specimens
that he had examined under this taxon:
Zeyher 84
and
Pillans 4864
. We were not able to locate
Zeyher 84
, so it is not possible to confirm if it is
S. riparius
, although it was collected from ‘Tafelberg’ (Table Mountain), which is from the same region as
Pillans 4864
.].
[Note: A
lectotype
was designated by T.L. Elliott as neither of the
two specimens
collected by Pillans were stored at B (the herbarium of the Botanic Garden and Botanic Museum Berlin-Dahlem)
—
the herbarium where K ukenthal € primarily worked. It is possible that K ukenthal € did examine
Pillans 4864
, and it was later destroyed during World War II.].
Caespitose, phyllopodic perennial graminoid, tall and robust (
Fig. 4C
).
Culms
terete, robust, relatively tall for this clade, (390
—
) 630
—
886(
—
1030) X (0.8
—
)1.3
—
1.9(
—
2.3) mm.
Leaves
basal, less than half the culm height or more, 1
—
2, (62
—
)230
—
540(
—
715) X 0.6‒0.9 (
—
1.3) mm, straight, proximally channelled, margin serrate above sheath.
Sheaths
dark reddish-black at base but paler above, firm, longitudinally striate.
Ligule
2-lobes not evident, firm, relatively short, 0.5
—
1.0(
—
1.3) mm long.
In
fl
orescence
a pseudolateral panicle, long, dense and relatively wide, with many spikes, (49
—
)60‒89 (
—
114) X (6
—
)12‒15(
—
19) mm, proximal rachis length (20
—
)28‒40 (
—
53) mm (
Fig. 4G
).
Proximal primary in
fl
orescence bracts
firm, apex acute to acuminate, usually channelled, narrow at base, (80
—
)96‒167 (
—
204) mm long, exceeding length of inflorescence at least slightly.
Spikes
often many and aggregated into dense clusters along rachis, 5‒13, (9.0
—
)12.0‒18.0(
—
24.0) mm long, overlapping.
Spikelets
lanceolate, aristate, (4.8
—
)5.4‒5.9(
—
6.2) X 1.0‒1.4(
—
1.6) mm, pedicellate, 2
—
4 spikelets per spike, dark reddish-brown in colour (
Fig. 5H
).
Proximal spikelet prophyll
1 per spikelet, well-developed, with notable, raised vein extending to mucro, 0.8‒1.0(
—
1.6) mm long, prophyll mucro sometimes long giving inflorescence a ‘bearded’ appearance, (1.8‒)2.9‒4.4(
—
6.4) mm long.
Rachilla
(0.4‒)1.0‒2.1(
—
3.5) mm long.
Glumes
5‒8 per spikelet, proximal glume (0.8‒)1.3‒1.8(
—
2.2) mm long, subproximal glume (1.0‒)1.4‒1.7(
—
2.5) mm long, narrow hyaline margins, upper glumes longer than basal ones, apex acute to obtuse. Glume mucros shortly cuspidate, proximal mucro (0.3‒)0.9‒ 1.5(
—
2.2) mm long, subproximal mucro (0.1‒)0.1‒0.7(
—
0.9) mm long.
Stamens
1‒3 per floret (usually 3), anthers 2.5‒3.0 mm long.
Stigmas
3-branched, vestigial stigmas of second bisexual floret absent (i.e. yet to be observed).
Perianth bristles
absent (i.e. yet to be observed).
Nutlet
broad elliptic, trigonous, yellowish in colour when young but maturing to reddish-brown in colour, 2.3‒3.2(
—
3.8) X
0.7‒ 1.3 mm
(
Fig. 6H
).
Nutlet beak
0.8‒1.5(‒2.5) mm long, hispid.
Flowering:
October
Distribution and ecology:
Schoenus riparius
has been reported from two locations (Camps Bay and Hout Bay) on the
Cape
Peninsula of
South Africa
(
Fig. 15
). Collections of this species have been made from damp sites between 150 and
200 m
.
Schoenus riparius
was last collected in 1946, and its existence has not been confirmed since that year. Recent searches by T.L. Elliott in 2017 and
2018 in
the Camps Bay and Hout Bay areas were not able to locate this species. Land transformation on the
Cape
Peninsula has reduced the amount of suitable habitat for
S. riparius
, so there is the possibility that
S. riparius
is now extinct.
Diagnosis:
Schoenus riparius
is a robust species, with relatively long and wide panicles (
Fig. 4C and G
). It is most like
S. loreus
, but it has channelled leaves that become terete distally compared to the non-channelled and flat leaves of
S. loreus
(
Fig. 3D
).
Schoenus australis
is also a relatively large and robust species (
Fig. 4D
), but it occurs on sites with coarse-textured soils, whereas
S. riparius
occurs on damp sites on the
Cape
Peninsula. The inflorescences of
S. australis
(
Fig. 4H
) are also shorter and thinner compared to those of
S. riparius
.
Schoenus crassus
is a third species that could be confused with
S. riparius
; however,
S. crassus
usually has firmer and stiffer basal leaves (
Fig. 3C
) compared to those of
S. riparius
. In addition,
S. crassus
has lighter reddish-brown coloured culm bases, inflorescences and spikelets than
S. riparius
(
Figs. 3
,
4
and
5
).
Fig. 15.
Documented locations of
S. riparius
.
Levyns (1947)
described the spikelets of
S. riparius
as cuspidate; however, the spikelets examined by T.L. Elliott were more aristate in shape.
Additional collections examined
South Africa
.
WESTERN CAPE
:
3318 (
Cape Town
):
Camps Bay, (
—
CD),
19 Oct 1946
,
Levyns
8721
(
BOL
,
K
);
17 Nov 1946
,
Levyns
8715
(
BOL
[2 sheets],
K
);
‘
Ad lat. Mont tabular. Infra Vam Campsbay’
, (
—
CD), Jul without year,
Zeyher
4432
(
SAM
)
.