Codon (plant)

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Codon
Codon royenii.jpg
Codon royenii
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Boraginales
Family: Codonaceae
Genus: Codon
L.

Codon is a small genus of plants from South Africa in the family Codonaceae [1] in the order Boraginales. [2] [3] It is the only genus in the family, [4] and comprises two species. [5]

Contents

Description

Codon species are annual to perennial herbs. The whole plants are densely covered with strong mineralised, unicellular trichomes on cystolithic foot-cells. The plants grow from strong taproots. [5]

The flowers are tetracyclic and polymerous. The whorls are 10- to 20-merous with a high variability even within one individual plant. Most common are 12-merous flowers. The sepals are free. The petals are fused up to three quarter of their length. The bases of the filaments are fused with the base of the corolla. The fused parts of the filaments form septa. These septa form separate nectar chambers. The gynoecium is superior and consists of two carpels. The base of the gynoecium forms a lobed nectary disc. Each lobe is covered with nectarostomata and secretes nectar in the nectar chambers. [6] The flowers are bell-shaped and white in C. royenii and saucer-shaped and yellow in C. schenckii.

The fruit is an apical-loculicidal capsule. [5] [6] Seeds are reticulately sculptured.

Taxonomy

Codon has been placed in the families Hydrophyllaceae and Boraginaceae. [2] Phylogenetic analysis in 2014 placed it as sister group to the Wellstediaceae and Boraginaceae s.str, [7] and the separate family Codonaceae was proposed. [1] As of December 2025, placement in Codonaceae is accepted by most taxonomic sources, [3] [8] [9] [10] [4] but not by Plants of the World Online which retains Boraginaceae. [11]

Species

As of December 2025, the genus includes two species: [4] [11]

ImageScientific nameDistribution
Codon royenii White Nectarcup.jpg Codon royenii L.Cape Provinces, Namibia
Codon schenckii Yellow Nectarcup1.jpg Codon schenckii SchinzCape Provinces, Namibia

References

  1. 1 2 Weigend, M.; Hilger, H. H. (2014-10-28). "Codonaceae-a newly required family name in Boraginales". Phytotaxa. 10 (1): 26. doi:10.11646/phytotaxa.10.1.3. ISSN   1179-3163.
  2. 1 2 Luebert, Federico; Cecchi, Lorenzo; Frohlich, Michael W.; Gottschling, Marc; Guilliams, C. Matt; Hasenstab-Lehman, Kristen E.; Hilger, Hartmut H.; Miller, James S.; Mittelbach, Moritz (2016-06-24). "Familial classification of the Boraginales" (PDF). Taxon. 65 (3): 502–522. doi:10.12705/653.5.
  3. 1 2 "Taxonomy browser (Codon)". www.ncbi.nlm.nih.gov. Retrieved 2021-07-23.
  4. 1 2 3 "Codon L." World Flora Online . Retrieved 2025-12-15.
  5. 1 2 3 Weigend, M.; Hilger, H. H. (2016). Flowering Plants. Eudicots. The Families and Genera of Vascular Plants. Springer, Cham. pp. 137–140. doi:10.1007/978-3-319-28534-4_9. ISBN   9783319285320.
  6. 1 2 Jeiter, Julius; Danisch, Fränze; Hilger, Hartmut H. (2016). "Polymery and nectary chambers in Codon (Codonaceae): Flower and fruit development in a small, capsule-bearing family of Boraginales". Flora - Morphology, Distribution, Functional Ecology of Plants. 220: 94–102. doi:10.1016/j.flora.2016.02.010.
  7. ↑ Weigend, Maximilian; Luebert, Federico; Gottschling, Marc; Couvreur, Thomas L.P.; Hilger, Hartmut H.; Miller, James S. (2014-10-01). "From capsules to nutlets—phylogenetic relationships in the Boraginales". Cladistics. 30 (5): 508–518. doi: 10.1111/cla.12061 . ISSN   1096-0031. S2CID   11954615.
  8. ↑ Stevens, P.F. (2001 onwards), "Codonaceae", Angiosperm Phylogeny Website, retrieved 2025-12-15
  9. ↑ "Codon L." Global Biodiversity Information Facility . Retrieved 2025-12-15.
  10. ↑ "genus Codon D. Royen". Germplasm Resources Information Network (GRIN) online database. Retrieved 2025-12-15.
  11. 1 2 "Codon L.", Plants of the World Online, Royal Botanic Gardens, Kew, retrieved 2025-12-15
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