Four new species and three taxonomic adjustments in Lachenalia (Asparagaceae: Scilloideae) from southern and western South Africa
Author
Duncan, Graham D.
0000-0002-3079-9613
Department of Biological Sciences, University of Cape Town, 7707 Rhodes Gift, South Africa & Kirstenbosch National Botanical Garden, South African National Biodiversity Institute, 7700 Newlands, South Africa g. duncan @ sanbi. org. za; https: // orcid. org / 0000 - 0002 - 3079 - 9613
g.duncan@sanbi.org.za
text
Phytotaxa
2023
2023-03-07
585
4
261
273
http://dx.doi.org/10.11646/phytotaxa.585.4.2
journal article
10.11646/phytotaxa.585.4.2
c78b339a-4ea5-4d66-8a33-af8020535056
1179-3163
7703809
Lachenalia komsbergensis
G.D.Duncan
,
sp. nov
.
(
Figs. 1
,
2
)
Type:—
SOUTH AFRICA
.
Northern Cape
: Komsberg Pass,
2.1 km
north of entrance to farm
De Plaat
on R354 from Matjiesfontein to Sutherland (3220
DC
), solitary plants and scattered clumps on flats among low scrub, in deep, beige alluvium above dry riverbed, in full sun, elev.
1144 m
,
8 October 2001
,
Duncan 459
(
holotype
NBG
)
.
This new species differs from
L. juncifolia
Baker (1871: 409)
in its leaves that are deeply canaliculate for their entire length, its spreading, white perianth with narrowly spreading stamens, its slightly larger globose seeds (1.2–1.3 ×
1.3–1.4 mm
) with a matt black testa and rugose primary sculpturing, a longer strophiole
0.5–0.6 mm
long, and in its taller stature up to
300 mm
high in full flower.
Deciduous, winter-green geophyte
150–300 mm
high. Bulb subglobose,
15–20 mm
in diam., offset-forming (1 or 2 offsets formed per bulb, but not necessarily every year); tunic multi-layered, outer tunics spongy, dark brown, inner tunics membranous, light brown; cataphyll translucent white, adhering to leaf bases, apex obtuse. Leaves 2, linear, 200–260 ×
1–15 mm
, suberect or recurved, deeply canaliculate, upper surface light green, lower surface light green in upper two thirds, heavily magenta- or purple-barred in lower third; apex acute; primary seedling leaf terete, erect. Inflorescence racemose, 10–48-flowered, flower head
40–120 mm
long; peduncle erect to suberect,
100–155 mm
long, rigid, light green, heavily speckled with dull purple; rachis light green and heavily purple-speckled in lower two thirds, white in upper third; lower bracts ovate, 1–4 ×
2–3 mm
, upper bracts lanceolate, 1–2 ×
1 mm
, white; pedicels suberect,
5–10 mm
long, white. Perianth zygomorphic, oblong-campanulate, suberect; tube cup-shaped,
3 mm
long, white; outer tepals ovate, 4–5 ×
3–4 mm
, apices flat, apical gibbosity deep pink; inner tepals obovate, 5–7 ×
3–5 mm
, translucent white, median keel light green in upper half, apices recurved. Stamens well exserted, narrowly spreading; filaments
8–10 mm
long, white; anthers 0.8–1.0 mm long, pollen yellow. Ovary obovoid, 3 ×
2 mm
, light green; style well exserted, straight,
9–10 mm
long, white; stigma minutely capitate. Capsule obovoid, 6–7 ×
4–5 mm
. Seed globose, 1.2–1.3 ×
1.3–1.4 mm
, matt, black; primary sculpturing rugose; strophiole
0.5–0.6 mm
long, ridged. Flowering time: September to October.
Etymology:—
The specific epithet
komsbergensis
commemorates the Komsberg in the southern Great Karoo, to which this species is endemic.
Other material examined:—
SOUTH AFRICA
.
Northern Cape
:
Komsberg Pass
,
2.1 km
north of entrance to farm
De Plaat
on R354 from
Matjiesfontein
to
Sutherland
(3220
DC
)
,
solitary plants and scattered clumps on flats among low scrub, in deep, beige alluvium above riverbed, in full sun, elev.
1144 m
,
1 September 2000
,
Summerfield
s.n.
(
NBG
)
;
Komsberg Pass
, farm
Damslaagte
(3220
DC
)
,
at river crossing,
19 October 2008
,
Saunders
&
Manning
3196
(
NBG
)
.
FIGURE 1.
Lachenalia komsbergensis
: detail of three flowering racemes in cultivation (A); single plant flowering in beige alluvium, Komsberg Pass (B); general view of Central Mountain Shale Renosterveld habitat, Komsberg Pass (C).
Lachenalia inflata
: single flowering plant in red sand north of Middelpos (D); single flowering plant in red clay west of Calvinia (E); general view of Roggeveld Karoo habitat north of Middelpos (F).
Lachenalia granitica
: detail of flowering spike in cultivation, with arrow showing a very long bract (G); flowering plant from Vredenburg in cultivation (H); spike of flowering and fruiting plant in Saldanha Granite Strandveld habitat near Vredenburg (I).
Lachenalia filamentosa
: flowering plants from Riviersonderend in cultivation (J); single flowering plant from De Hoop Nature Reserve in cultivation (K); two plants in early fruiting stage in De Hoop Limestone Fynbos habitat, De Hoop Nature Reserve (L). Photographs: A-D, F-K by Graham Duncan; E by Adam Harrower; L by David Gwynne-Evans.
FIGURE 2
. Distribution of
Lachenalia komsbergensis
in the southern Great Karoo of the Northern Cape, South Africa (inverted black triangle),
Lachenalia inflata
in the western Great Karoo, Northern Cape, South Africa (black triangles),
Lachenalia granitica
along the Cape West Coast, Western Cape, South Africa (black squares) and
Lachenalia filamentosa
along the Cape West Coast, Breede River Valley and Overberg in the Western Cape, South Africa (black dots).
Notes:—
The first collection of flowering specimens was made at the
type
location by G.C. Summerfield in
September 2000
.
A subsequent record of flowering plants was made at the same location by
G.D. Duncan
on
8 October 2001
, when the
type
specimens were collected and habitat photographs were taken. Material from this collection has since flowered every year in cultivation in the bulb nursery at Kirstenbosch. A third collection at late flowering stage was made close to the
type
location by R. Saunders and J. Manning on
19 October 2008
.
Diagnostic features and affinities:—
Lachenalia komsbergensis
is recognised in flower by an erect or suberect, rigid, light green peduncle that is heavily speckled with dull purple, bearing a raceme of small oblong-campanulate, spreading, white and pink flowers carried on white, suberect pedicels (
Fig. 1 A
). It has shallowly cup-shaped perianth tubes and narrowly spreading tepals. The outer tepals have a prominent deep pink median keel and apical gibbosity, and the strongly protruding inner tepals have a dull pink median keel. The flowers have bracts that are ovate at the base of the inflorescence and lanceolate above, and well exserted, narrowly spreading, white stamens. The inflorescence emerges towards the end of the growing season, as the leaves start to wither. The species is further recognised by two linear, suberect or recurved, deeply canaliculate, conduplicate leaves, with acute apices. The upper and lower surfaces are light green, and the lower surfaces are heavily magenta- or purple-barred in the lower third, and green-barred in the upper two thirds. The primary seedling leaf is terete, with erect orientation. The fruit is an obovoid capsule containing globose, matt black seeds with rugose primary sculpturing, and ridged strophioles.
Lachenalia komsbergensis
is included within subsect.
Lachenalia
of sect.
Lachenalia
(
Duncan
et al
. 2022
)
. It was initially considered to be a tall-growing form of
L. juncifolia
, but in phylogenetic analysis it was retrieved as sister to two accessions of
L. longibracteata
Phillips (1931: 405)
, in a phylogenetically strongly isolated position from
L. juncifolia
, the latter falling within sect.
Linearifoliae
(
Duncan
et al
. 2022
).
L. komsbergensis
differs from
L. juncifolia
in having leaves that are deeply canaliculate for their entire length (versus slightly canaliculate in the lower two thirds and terete in the upper third), a spreading, mostly white perianth (versus cernuous and cream-coloured, pink, magenta or purple), narrowly spreading stamens (versus straight), a taller stature up to
300 mm
high (versus up to
200 mm
high), slightly larger seeds (1.2–1.3 ×
1.3–1.4 mm
) with a matt black testa and rugose primary sculpturing (versus 1.1– 1.2 ×
1.3 mm
, with a glossy black testa and smooth primary sculpturing), and a substantially longer strophiole
0.5–0.6 mm
long (versus
0.2 mm
long). Furthermore,
L. juncifolia
has a much longer flowering period (August to December) and a much wider distribution from Calvinia in the western Great Karoo to Herbertsdale in the southern
Cape
(
Duncan 2012
).
Distribution and habitat:—
Lachenalia komsbergensis
occurs in the Succulent Karoo biome in the southern part of the
Northern Cape
, and is endemic to the Komsberg, a component of the Hantam-Roggeveld Centre of Plant Endemism (
Van Wyk & Smith 2001
,
Mucina & Rutherford 2006
,
Clark
et al
. 2011
). It is highly localised to open flats adjacent to a seasonal river in the southern Komsberg, at an elevation of
1144 m
(
Fig. 2
). The area receives most of its rainfall in winter but is transitionary between winter and summer rainfall regimes (
Clark
et al
. 2011
). The plants occur as scattered solitary individuals or in small groups of up to four plants on flats in deep, beige alluvium. The bulbs are shallowly seated and occur among low, sparse, scrubby vegetation including perennials of the family
Asteraceae
, in Central Mountain Shale Renosterveld, a vegetation
type
which occupies a borderline position straddling the Fynbos, Succulent Karoo and marginally the Nama Karoo biomes (
Mucina & Rutherford 2006
) (
Fig. 1 B, C
). The species flowers late in the spring season (late September to October), at a time when the leaves are already beginning to desiccate.