Disocactus

Disocactus Lindl. ()
🌵 Author(s)
🌵 Type Disocactus biformis
Etymology

Greek dis- ‘twice’ + Greek isos ‘equal’ + Cactus. Named “in allusion to the distinctive character of the genus”, i.e. the tepals and sepals being equal in number and “similar in form and colour” (Lindley).

Theodor Rümpler (Handb. Cacteenk. (ed. 2 - Rümpler). 1886) claims the name refers to the equal number (4) of petals and sepals, hence his German name Vierblatt-Cactus ‘four-leaf cactus’. Eggli & Newton (Etymological Dictionary of Succulent Plant Names. 2004) explain it as a reference to “the leaf-like flattened (‘with two identical sides’) stems”, but this is not supported by Lindley’s protologue.

Gustav Kunze (Bot. Zeitung (Berlin) 3: 533. 1845) corrected the name, which he considered “incorrectly formed” and “very inappropriate” because of the similarity to Discocactus, to Disisocactus. The morpheme combination dis + isos + Cactus would indeed regularly result in the compound Disisocactus, but haplology (the simplification of a word by omitting one of two similar sounding syllables) is a known phenomenon in both ancient Greek (amphiphoreus > amphoreus) and Latin (idololatria > idolatria) and is also found in other generic names, e.g. Gymnema (“Gymnonema”), Hartmanthus (“Hartmannanthus”), Microcos (“Micrococos”), and Oxystophyllum (“Oxyxystophyllum”). Kunze’s “correction” was taken up by several other authors, but today the original spelling Disocactus is again universally accepted. Not to be confused with ×Disisocactus Doweld (2002), the ill-named nothogenus for hybrids between Disocactus and Disisorhipsalis.

Disocactus biformis. Image credit: Lindley 1845

How to cite

Maarten H.J. van der Meer (2023 Jul 21). Disocactus. Dictionary of Cactus Names. Retrieved from https://www.cactusnames.org/Disocactus

Pronunciation
[dis-o-KAK-tus]

A.T. Johnson, H.A. Smith & A.P. Stockdale (2019): Plant Names Simplified, 3rd Edition

[DY-soh-kak-tus]

Ross Bayton (2019): The Garderner's Botanical

[Disocáctus]

Helmut Genaust (1996): Etymologisches Wörterbuch der botanischen Pflanzennamen, 3. Auflage

“Botanical Latin is essentially a written language, but the scientific names of plants often occur in speech. How they are pronounced really matters little provided they sound pleasant and are understood by all concerned.”

William T. Stearn (1983): Botanical Latin, 3rd Edition: 53