Papyrocactus Doweld, nom. nov.

≡ Toumeya Britton & Rose, Cactaceae 3: 91. 1922, nom.illegit.non Tuomeya W.H.Harvey,Nereis Bor.Amer. 3: 64. 1858 ( Rhodymeniophyta-Lemaneaceae).

Type— Papyrocactus papyracanthus (Engelmann) Doweld, comb. nov.

≡ Mammillaria papyracantha Engelmann [in Gray] Mem. Amer. Acad. Arts Sci. Ser. 2, 1, Art. 1: 49. 1849.

Holotype — USA: New Mexico: between the lower hills near Santa Fé, A. Fendler # 12, 15 May 1847 (MO 2017206).

Etymology: from Greek stem papyros, paper-like spines of the cactus.

In a revision of the tribe Cacteae, subtribe Sclerocactinae Doweld of the Cactaceae (Doweld 1998, 2000), the genus Toumeya Britton & Rose (1922) was accepted as a distinct genus on the basis of the comprehensive complex of characters, including newly added seed micromorphology in particular. However, the parahomonym was known at that time, and Doweld (in litt.) submitted an official request to the General Committee of Botanical Nomenclature for the binding decision whether the pair of parahomonyms, Toumeya Britton & Rose (1922) and Tuomeya W.H. Harvey (1858), are sufficiently alike to be confused. The Committee for Spermatophyta resolved the case and confirmed that these generic names are homonyms (Brummitt 2004: 824), and the General Committee approved this decision (Barrie 2006: 798). In this connection, a new replacement name for cacti is validated here in anticipation of the preparing new revision of the systematics of the tribe Cacteae .