Taxonomic revision of the southern African species of the genus Cynoglossum L. (Boraginaceae)
Author
Madika, Lydia K.
Department of Botany & Plant Biotechnology, Faculty of Science, University of Johannesburg, PO Box 524 Auckland Park 2006, Johannesburg, South Africa
Author
Moteetee, Annah Ntsamaeeng
Department of Botany & Plant Biotechnology, Faculty of Science, University of Johannesburg, PO Box 524 Auckland Park 2006, Johannesburg, South Africa
amoteetee@uj.ac.za
text
PhytoKeys
2022
2022-03-15
193
9
42
http://dx.doi.org/10.3897/phytokeys.193.72270
journal article
10.3897/phytokeys.193.72270
8.
Cynoglossum spelaeum
Hilliard & B.L.Burtt
in
Notes Roy. Bot. Gard.,
Edinburgh
37(2): 287 (1979)
.
Cynoglossum basuticum
Weim
.ex Guillarmod, Fl.
Lesotho
233 (1973), nom. nud
.
Type.
South Africa
♀♂,
KwaZulu-Natal
,
Underberg
(2929):
Underberg District
,
Cobham Forest Station
,
Polela valley
(-CD),
20 Mar 1977
,
O.M. Hilliard
and
B.L. Burtt
9728
(E,
holotype
image! K-image!, NU-image! PRE-image! [2 sheets]
isotype
)
.
Perennial herbs, ca.
0.4–0.5 m
in height. Basal leaves 130–235×
25–35 mm
, spathulate-obtuse, soft hairs, deciduous, margins entire. Stem leaves 40–80×
10–25 mm
, obtuse shaped, dark green adaxial surface, grey green abaxial surface, smooth margins, soft hairs, sparsely packed. Trichomes unicellular, simple on both leaf surfaces, soft. Inflorescence corymbose panicle; threadlike pedicel
5 mm
long. Calyx ca. 1.5–2.0 mm long, lobes lanceolate-oblong, softly hairy on the outer surface, inner surface smooth, apex acute. Corolla white; lobes ca. 3×
3 mm
diameter, obtuse. Nutlets ovoid, ca. 4×
5 mm
; glochidia more marginal and acentric, marginal glochidia are longer compared to the acentric glochidia (
Figure 17
).
Phenology.
December to March.
Figure 17.
Morphological features of
C. spelaeum
A
line drawing of a fruiting branch showing stem with alternate, sessile, spathulate leaves
B
SEM micrograph of nutlet showing more marginal and acentric glochidia
C
close-up SEM micrograph showing glochidia with multiangular hooks. Voucher specimen:
A. Nicholas
and
B. Isaacs 1965
(PRE). Drawing scale 8.0 mm. SEM images scale bars: 1 mm (
B
); 200 µm (
C
).
Conservation status.
Least Concern (
Raimondo et al. 2009
).
Diagnostic characters.
This species is characterised by leaves that are sparsely covered with hairs that have a softer feel, which distinguishes it sharply from all the other southern African species which have either brittle or woolly hairs. The abaxial leaf surface has a grey-greenish appearance which is also a unique character of this species.
Distribution and habitat.
The species is distributed in South Africa (Eastern Cape, Free-State, and KwaZulu-Natal Provinces) and Lesotho (
Figure 18
). It grows in loose sandy soil at the edge of an overhang.
Additional specimens examined.
South Africa. KWAZULU-NATAL: 2729 (Utrecht): Ncandu State Forest (-
DC
),
8 May 1984
,
A. Nicholas
and
B. Isaacs 1965
(
PRE
). 2929 (Underberg): Allandale, Lion’s River District (-
BC
),
24 Jan 1978
,
O.M. Hilliard
and
B.L. Burtt 11258
(
NU
); Giant’s Castle Nature Reserve (-
BC
),
07 Jan 1988
,
A. Abbott 4064
(
NH
);
3 Feb 1976
,
O.M. Hilliard
and
B.L. Burtt 8904
(
NU
);
2 Jan 1978
,
O.M. Hilliard
and
B.L. Burtt 11172
(
NU
);
20 Nov 1985
,
O.M. Hilliard
and
B.L. Burtt 18242
(
NU
,
PRE
); Bulwer District (-
DD
),
8 Jan 1974
,
M.A. Rennie 507
(
NU
);
8 Mar 2019
,
A.N. Moteetee
and
L.K. Madika AL012
(
JRAU
). EASTERN CAPE: 3127 (Lady Frere): Elliot District (-
BB
),
22 Jan 1979
,
O.M. Hilliard
and
B.L. Burtt 123427
(
NU
). 3226 (Fort Beaufort): Amatole Mountain (-
DB
),
16 Feb 1986
,
P.B. Phillipson 1294
(
PRE
).
Figure 18.
Known distribution of
Cynoglossum spelaeum
in southern Africa based on the specimens examined.
Lesotho. 2927 (Maseru): Laikopile Mountain (-
CD
),
Jan 1918
,
A. Dieterlen 40799
(
PRE
).
Taxonomic notes.
Cynoglossum spelaeum
is quite distinctive among the southern African species having uniquely shaped (i.e., spatulate to obtuse) and coloured (i.e., deep green adaxial surface, grey green abaxial surface) leaves, that almost seem leathery but contain few soft trichomes. It is also the only species among the southern African species that has completely white flowers. Although
Hilger et al. (2015)
indicated that the species does not belong to genus
Cynoglossum
, they did not elaborate the reasons for the exclusion. Nonetheless, the species fits the generic description of four glochidiate nutlets that are adapted for zoochory. In addition, preliminary molecular data (
Madika 2020
), showed a close relationship between
C. coeruleum
subsp.
johnstonii
var.
mannii
,
C. lanceolatum
, and
C. spelaeum
.