A revision of Lebeckia sect. Lebeckia: The L. sepiaria group
Author
le Roux, M. M.
Department of Botany and Plant Biotechnology, University of Johannesburg, P. O. Box 524, Auckland Park 2006, South Africa
Author
Van Wyk, B. - E.
Department of Botany and Plant Biotechnology, University of Johannesburg, P. O. Box 524, Auckland Park 2006, South Africa
bevw@na.rau.ac.za
text
South African Journal of Botany
2007
2007-01-31
73
1
118
130
http://dx.doi.org/10.1016/j.sajb.2006.09.005
journal article
10.1016/j.sajb.2006.09.005
3a3b284a-51fc-46db-b751-28978c8e5adf
7958313
4.3.
L. gracilis
L. gracilis
Eckl. and Zeyh.,
Enum.: 192 (1836)
; Benth. in
Hook.,
Lond. J. Bot. 3: 358 (1844)
.
Type:
South Africa
, “Zwartkopsrivier” [3322 CD],
Ecklon and Zeyher 1336
(
SAM
!, specimen in middle of the sheet,
lectotype
, designated here
;
P
!,
S
!, isolectotypes)
.
L. sepiaria auct. non
(L.) Thunb
.: Eckl. and
Zeyh., Enum.: 191 (1836)
; Harv. in Harv. and Sond., Fl. Cap. 2: 86 (1862);
Goldblatt and Manning, Cape Plants,
Strelitzia 9: 493 (2000)
. [Harvey cited a Thunberg specimen (
Thunberg s.n. sub Herb. Thunberg 16422
) which is indeed this species. However, Thunberg based his description on a specimen from Cape Town “Leeuwenberg”, but he explicitly cited
Spartium sepiarium
of Linnaeus,
q.v
.]
L. ambigua
E. Mey., Com.
: 34 (1836)
,
pro parte minore
.
Erect, glaucous suffrutex,
0.15
−
0.8 m
in height.
Leaves
simple, acicular, articulated near the middle; leaf density 3–6 per
10 mm
length of stem.
Inflorescences
terminal,
44–172 mm
long; rachis furrowed; flowers numerous, relatively dense (5–7 per
10 mm
length of rachis), relatively small in size (
6–8 mm
long); pedicel 1.5–3.0 mm long; bract lanceolate, acute, ±
2 mm
long; bracteoles triangular, acuminate, ±
1 mm
long.
Calyx
2.5–4.5 mm
long, tube
1.5–3.5 mm
long, lobes
0.7–1.5 mm
long; ± equally lobed; lobes deltoid, tips minutely pubescent inside.
Standard
widely oblong to suborbicular or obovate, 4.0–6.5 × 2.0–
3.5 mm
; apex obtuse; claw
1.5–2.5 mm
long.
Wings
oblong, longer than the keel, 4.0–6.5 × 1.0–
2.5 mm
, with 11–14 rows of sculpturing; apex obtuse; claws 1.5–2.0 mm long.
Keel
rostrate, 5–6 ×
1.5–2.5 mm
, sometimes with pockets; claws
1.5–2.5 mm
long.
Pistil
subsessile; ovary 5.5–7.5 ×
0.6–0.8 mm
long, linear; ovules many (9–11); style
1.5–3.5 mm
long, curved upwards.
Pods
linear, straight or very slightly falcate, up to 37 ×
2–3 mm
; dehiscent; semi-terete; fruit wall thin, membranous.
Seeds
reniform-orbicular, ± 1.8 ×
1.5 mm
, rugose, pale brown, mottled dark brown to black; hilum dark brown (
Fig. 9
).
Fig. 9. Morphology of
Lebeckia gracilis
: (a) Lateral view of flower; (b) abaxial view of bract and bracteoles; (c) abaxial view of calyx with the upper lobes to the left; (d) standard petal; (e) wing petal; (f) keel petal; (g) anthers; (h) long, basifixed anther, carinal (intermediate) anther and short, dorsifixed anther; (i) pistil; (j1 – j2) lateral view of pods; (k) cross section of pod; (l) leaf. Vouchers: (a) from
Heginbotham 163
(NBG); (b, e) from
Esterhuysen 23529
(BOL); (c, f, g, h, i) from
Bohnen 7617
(NBG); (d) from
Leighton 1894
(BOL); (j1) from
Hutchinson 1478
(BOL); (j2) from
Ecklon and Zeyher 1336
(S); (k) from
Le Roux
,
Boatwright
,
Magee and Van Wyk 17
(JRAU); (l) from
Wurts 2234
(NBG). Scale bars: 1 mm.
4.3.1. Diagnostic characters
L. gracilis
is similar to
L. ambigua
but differs in its calyx that is ± equally lobed and with the lobes shorter than the tube (calyx subequally lobed and the lobes as long as the tube in
L. ambigua
) (
Fig. 9
).
L. gracilis
also differs from
L. ambigua
in its shorter and more congested racemes. The two species are allopatric.
4.3.2. Distribution and habitat
L. gracilis
has a distinctively coastal distribution, from Bredasdorp in the Western Cape Province eastwards to Port Elizabeth in the Eastern Cape Province (
Fig. 10
). All known localities are below
300 m
altitude. Those in the west experience winter rainfall, while those in the east (around Port Elizabeth) have a higher proportion of summer rain. Plants grow in deep sandy soil.
4.3.3. Specimens examined.
–
3322
(
Oudtshoorn
):
Fairy Knowe
(–
DC
),
Guillarmond
8257
(
PRE
)
;
Rondevlei
(–
DC
),
Sachse
670
(
PRE
)
;
Wilderness
(–
DC
),
Van Niekerk
223
(
BOL
)
;
Ruigtevlei at Zwart River
(–
DD
),
Fourcade
1534
(
BOL
,
NBG
,
PRE
)
.
–
3324
(
Steytlerville
):
Zwartkopsrivier
(–
DC
),
Ecklon
and
Zeyher
1336
(
P
,
S
,
SAM
)
,
Zeyher
2293
(
P
,
S
)
;
Gamtoos River
(–
DD
),
Gillett
2361
(
NBG
)
.
–
3325
(
Port Elizabeth
):
Humewood
(–
DC
),
Paterson
773
(
BOL
)
.
–
3420
(
Bredasdorp
):
De Hoop
(–
AD
),
Morley
139
(
PRE
)
;
Melkbosheuwel
(–
BC
),
Burgers
2461
(
NBG
)
;
Potberg
area (–
BC
),
Derdejaarsekskursie
84/C10
(
NBG
)
;
Potberg
(–
BC
),
Esterhuysen
23259
(
BOL
)
;
De Hoop
(–
BC
),
Fellingham
701
(
PRE
)
;
The Poort
(–
CA
),
Henderson
1829
(
NBG
),
Morris
268
(
NBG
)
;
Bredasdorp Poort
(–
CA
)
,
Heginbotham
163
(
NBG
)
.
–
3421
(
Riversdale
):
Oude Tuin near Albertinia
(–
AB
),
Muir
1852
(
BOL
,
PRE
)
;
Stilbaai
(–
AD
),
Jordaan
18607
(
NBG
)
;
Stilbaaihoogte
(–
AD
),
Bohnen
7617
(
NBG
)
,
Le Roux
,
Boatwright
,
Magee
and
Van Wyk
17
(
JRAU
)
.
–
3422
(
Mossel Bay
):
Brak River
(–
AA
),
Young
5514
(
BOL
)
;
Belvedere
(–
BB
),
Duthie
510
(
NBG
)
;
Goukamma
(–
BB
)
,
Wurts
2234
(
NBG
)
.
–
3423
(
Knysna
):
Between Knysna and Plettenberg Bay
(–
AA
),
Pappe
s.n.
(
S
,
SAM
)
;
Plettenbergbaai
(–
AB
),
Anon
s.n. sub
STEU 13540
(
NBG
)
.
–
3425
(
Port Elizabeth
):
Schoenmakers Kop
(–
AB
),
Story
3654
(
PRE
)
.