Aspalathus quartzicola C.H.Stirt. & Muasya
Common names: No reported common names.
Aspalathus quartzicola is one of few species that occur in quartz patches (quartz-silcrete outcrops); a very specialized habitat, hence its species name. It takes the form of an ancient tree growing horizontally across these quartz patches, creating magnificent displays during and after flowering.
Aspalathus quartzicola is a mat-forming shrub, with branches densely packed and growing up to 20 mm high. It has distinct twisted stems of 30 mm thick (stems look like ancient tree stumps). It is a respouter, as it dies after fire and regenerates from burned stems. Leaflets are linear, succulent, upright and hairless, arranged in dense clusters.
The inflorescence is 1- or 2-flowered and flowers are found on the ends of the shoots arising along the branches. The flowers form a typical pea flower, are white with a distinct pink keel tip and have a sweet-smelling scent. This species flowers from August to September (in spring).
Its fruits are borne upright; they are flatly egg shaped, hairless, and glossy, with a sharp point and covered with a network of veins. When fruits are young they are bright green and then turn pale brown when mature (7 × 3 mm). Seeds are 2.0–2.3 × 1.8–2.0 mm and tan with brown blotches.
Aspalathus quartzicola is a long-lived plant, with an estimated life span of 40 years (Curtis et al. 2014).
The species is listed as Vulnerable (VU), since it is locally common, but is largely distributed outside formal protected areas. Since it is a habitat specialist of quartzitic outcrop and silcrete, habitat loss to cultivation is not a direct threat; however, over-grazing and habitat degradation are secondary threats. This species can be protected by fencing off the remaining remnants, to control livestock access to these sensitive areas (Curtis et al. 2014). More recently some of the populations have been included within conservation areas such as Haarwegskloof, home of the Overberg Renosterveld Conservation Trust.
Distribution and habitat
This species is a habitat specialist. It is found on flat areas within white quartz patches, within the Eastern Rûens Shale Renosterveld. It also grows on silcrete. It is distributed from Bredasdorp to Heidelberg between 170 and 300 m altitude.
Derivation of name and historical aspects
Aspalathus quartzicola is a species within the largest endemic genus Aspalathus within the Fabaceae family of South Africa. The epithet quartzicola makes reference to its restricted distribution to quartz outcrops within the Overberg region. More specifically, the epithet quartzi- refers to the substrate and cola is the Latin suffix meaning ‘inhabitant of’ or ‘residing on’.
This species was discovered by Dr Charles Stirton who recognised that it differed from A.incompta ( pers.comm. Odette Curtis, a Renosterveld conservationist in the Overberg District (See http://overbergrenosterveld.org.za/ ). Aspalathus quartzicola is one of many iconic species endemic to the Overberg Rûans Shale Renosterveld. This species is very distinct from similar species such as Aspalathus acutiflora R.Dahlgren and Aspalathus incompta Thunb., by having a mat-forming growth form (Curtis et al. 2014).
The sweet-scented flowers attract honey-bees (Apis mellifera subsp. capensis), the main pollinators of this species. Little is known about seed dispersal and other ecological aspects of the species.
Aspalathus quartzicola has no known uses. It is a long-lived and slow-growing species; hence may have potential as a bonsai plant if it can be cultivated.
Growing Aspalathus quartzicola
Aspalathus quarticola, even though it is a very beautiful and would make a pretty garden plant, is a habitat specialist with specific growth requirements (quartz-silcrete substrate). It has not been cultivated and this is so for most Aspalathus species, excluding Aspalathus linearis (which is cultivated for rooibos).
Further, legume species in general, make symbiotic associations with nodulating bacteria, and in some species, this association is very specific, with a 1:1 ratio of one host plant to one bacterium (Phalane et al. 2008). Hence, if the specific bacterial associate is not present in the soil, the plant might not be able to grow.
- Curtis, O.E., Stirton, C.G. & Muasya, M. 2013. A conservation and floristic assessment of poorly known species on rich quartz-silcrete outcrops with Rûans Shale Renosterveld. South African Journal of Botany 87: 99–111.
- Curtis, O.E., Stirton, C.H., Muasya, M. & Raimondo, D. 2014. Aspalathus quartzicola C.H.Stirt. & Muasya. National Assessment: Red List of South African plants version 2014.1. Accessed on 2015/02/12.
- Overberg Lowlands Conservation Trust. http://overbergrenosterveld.org.za/haarwegskloof-renosterveld-nature-reserve/: Accessed on 11/02/2014.
- Phalane, F.L., Steenkamp, E.T., Law, I.J. & Botha, W.F. 2008. The diversity of Root Nodule bacteria associated with Lebeckia species in South Africa. In Biological nitrogen fixation. Springer: Dordrecht, The Netherlands: 119, 120.
Dewidine van der Colff
Threatened Species Program (TSP)/ Custodians of Rare and Endangered Wildflowers (CREW)
Plant Type: Ground Cover, Shrub
SA Distribution: Western Cape
Soil type: Clay
Flowering season: Spring
Flower colour: White, Pink
Aspect: Full Sun
Gardening skill: Challenging