Rhodochiton atrosanguineus

Rhodochiton atrosanguineus is a herbaceous perennial vine^[2] native to Mexico. It has been cultivated as an ornamental plant since at least 1836.^[3]

Rhodochiton atrosanguineus
In cultivation
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Lamiales
Family:	Plantaginaceae
Genus:	Rhodochiton
Species:	R. atrosanguineus
Binomial name
Rhodochiton atrosanguineus (Zucc.) Rothm.[1]
Synonyms[1]
Lophospermum atrosanguineum Zucc. Lophospermum rhodochiton D.Don Maurandya atrosanguinea (Zucc.) G.Nicholson Rhodochiton volubilis Zucc. ex Otto & A.Dietr., nom. illeg.

Although the specific epithet is sometimes spelled atrosanguineum, chiton in Greek is masculine,^[4] so the ending is correctly -us.^[5]

Rhodochiton atrosanguineus is commonly known as purple bell vine or simply purple bell.^[2]

All Rhodochiton species are sometimes placed in the genus Lophospermum.^[6]

Description

Its dangling flowers have a pink, bell-shaped calyx of sepals surrounding a protruding, tubular corolla of purple-black petals.^[6] It has somewhat hairy, heart-shaped leaves, often with purple venation. The vine can reach three metres in length in perfect conditions, but more-likely 1.5-2.5 metres.^[2] The seeds are 3mm across.

Taxonomic history

Wayne J. Elisens has outlined the somewhat confused taxonomic history of the name of this species.^[7] In 1829, Joseph Gerhard Zuccarini sent seeds and a description to individuals and botanical gardens under the name "Rhodochiton volubile", considering it to be a new genus; however the name was not formally published. In 1832, Zuccarini decided that it was actually a Lophospermum, and published the name Lophospermum atrosanguineum, writing that "I held it at first to be new genus and sent the seeds obtained in the summer of 1829 to several gardens under the name Rhodochiton volubile. The figure in the Botanical Register has convinced me of the identity of the genus."^[8] Not knowing of Zuccharini's change of name, in particular his publication of the epithet atrosanguineum, in 1834 Christoph Friedrich Otto and Albert Gottfried Dietrich published and illustrated Rhodochiton volubilis, an illegitimate name since a prior epithet existed.^{[Note 1]} In 1943, Rothmaler provided a legitimate combination in the genus Rhodochiton, namely Rhodochiton atrosanguineus.^{[5][Note 2]}

Cultivation

Rhodochiton atrosanguineus has gained the Royal Horticultural Society's Award of Garden Merit.^[10][11]

This plant is undemanding if given full sun or near-full sun, well-drained soil, and general care. It will tolerate cold temperatures, but not freezing.^[2]

Propagation is by seed sown in spring, or at 15-18 °C.

Plants can be pruned in late winter to manage size and shape.

• 
  Flower from underneath
• 
  Developing seed pod
• 
  Seeds (3mm across)

Notes

1. The name as published originally was Rhodochiton volubile. However, chiton in Greek is masculine, so the epithet should be volubilis.^[9] The International Code of Nomenclature for algae, fungi, and plants requires incorrect genders to be corrected.
2. The name as published originally was Rhodochiton atrosanguineum, but as noted above it should be corrected to Rhodochiton atrosanguineus.^[5]

References

1. "Rhodochiton atrosanguineum", The Plant List, retrieved 2014-07-14
2. "Rhodochiton atrosanguineus", RHS Gardening, Royal Horticultural Society, retrieved 2014-12-09
3. Paxton, J. (1836), "Select List of Ornamental Creepers", Paxton's Magazine of Botany, and Register of Flowering Plants, 2: 33–37, retrieved 2014-07-13 – under the synonym Rhodochiton volubile
4. Stearn, W.T. (2004), Botanical Latin (4th (p/b) ed.), Portland, Oregon: Timber Press, p. 384, ISBN 978-0-7153-1643-6
5. "Rhodochiton atrosanguineus (Zucc.) Rothm.", Tropicos.org, Missouri Botanical Garden, retrieved 2014-07-20
6. Elisens, Wayne J. (1985), "Monograph of the Maurandyinae (Scrophulariaceae-Antirrhineae)", Systematic Botany Monographs, 5: 1–97, doi:10.2307/25027602, JSTOR 25027602 – all Rhodochiton species placed in Lophospermum
7. Elisens 1985, p. 4
8. Zuccarini, J.G. (1832), "Plantarum novarum vel minus cognitarum, quae in horto botanico herbarioque regio monacensi servantur", Abhandlungen der Mathematisch-Physikalischen Classe der Königlich Bayerischen Akademie der Wissenschaften, 1: 289–396, retrieved 2014-07-22, pp. 306–307 – "German: Der hiesige Garten erhielt im Jahr 1828 durch Hrn. Baron Karwinski Samen einer dritten Art dieser schönen Gattung, welche im wärmeren Europa eine bedeutende Stelle unter den feineren Zierpflanzen einzunehmen verspricht. Ich hielt sie anfangs, da Don's Gattungscharakter in einigen Dingen abweicht, für ein neues Genus und versendete die im Sommer 1829 gewonnenen Samen unter dem Namen Rhodochiton volubile an mehrere Gärten. Die Abbildung im Botanical Register hat mich von der Identität der Gattung überzeugt." (The local garden received in 1828 from Baron Karwinski seeds of a third species of this beautiful genus, which, in the warmer parts of Europe, promises to take a significant place among the finer ornamental plants. Because Don's generic character differs in some ways, I held it at first to be new genus and sent the seeds obtained in the summer of 1829 to several gardens under the name Rhodochiton volubile. The figure in the Botanical Register has convinced me of the identity of the genus.)
9. Farr, E.R.; Zijlstra, G., eds. (2013), "ING Database Rhodochiton", Index Nominum Genericorum (Plantarum), retrieved 2014-07-23
10. "RHS Plantfinder - Rhodochiton atrosanguineus". Retrieved 2 October 2018.
11. "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 84. Retrieved 2 October 2018.