Argyroderma subrotundum L.Bolus
Sub-rounded argyroderma
Argyroderma subrotundum is a mesemb of the family Aizoaceae described by Louisa Bolus, endemic to the quartz fields of Namaqualand, South Africa. The epithet 'subrotundum' (nearly round, sub-rounded) describes the shape of the bilobed body, intermediate between a perfect globe and slightly flattened. It is one of the species in the genus with the most rounded and uniform body form, giving it a particularly clean and geometric appearance.
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Overview
| Category | Classification |
|---|---|
| Family | Aizoaceae |
| Genus | Argyroderma |
| Growth Habit | Acaulescent perennial succulent; body formed by 1–2 pairs of very rounded (sub-spherical), grey-silvery leaves. Active growth in autumn-winter; summer dormancy. |
| Conservation Status | Data Deficient (DD); distribution restricted to Namaqualand. |
| pH Target | 6.5–7.5 |
| Type | Very sandy, extremely well-drained, low in nutrients |
Origin & Habitat
Morphology
Two succulent leaves fused into an almost perfect sub-spherical form, grey-silvery. The central cleft is very narrow, enhancing the nearly spherical body appearance.
ecoSolitary flowers with linear petals emerging from the cleft in autumn-winter. The contrast between the rounded silvery body and the open petals is especially striking.
ecoDeep, contractile roots adapted to the sandy quartz field substrate.
ecoThe almost spherical body among white quartz pebbles represents the most perfect mimicry in the genus; the plant is practically indistinguishable from a rounded quartz pebble.
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Requirements
Soil & Substrate
Type
Very sandy, extremely well-drained, low in nutrients
groups Beneficial Associations
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Propagation Strategy
- 1 Sow in autumn in very fine mineral sand without covering seeds
- 2 Keep moist under glass at 15–22 °C until germination
- 3 Very sensitive seedlings; ventilate daily
- 1 Divide in autumn at the start of active growth
- 2 Callous 2–3 days; plant in mineral sand
S
Watering in summer
Every 3–4 years in autumn
Very diluted mineral once in autumn from year two. Never in summer.
Uses & Applications
Precautions / Toxicity
Non-toxic
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Plant Health
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"A. subrotundum exhibits the most extreme lithophytic mimicry in the genus Argyroderma thanks to its almost perfectly spherical form. This morphological convergence with the rounded quartz pebbles of the habitat is a fascinating example of adaptive evolution."
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Scientific Integrity
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Sources
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Discussion
Disclaimer
This species record is provided for educational and informational purposes only. Jardín Roca Negra does not guarantee the accuracy or completeness of the data. Content is community-curated and may be subject to revision; it should not replace advice from a qualified botanist. This species may be toxic, invasive, or subject to legal restrictions — verify before handling or cultivating. Jardín Roca Negra accepts no liability for any harm arising from reliance on this information. Images are reproduced under Creative Commons or equivalent free licenses; credits are noted below each image.