Orobanche alba subsp. major, (Celak.) Zazvorka, 2000

Uhlich, Holger & Rätzel, Stefan, 2015, A contribution to the taxonomy and phytogeography of Orobanche alba Steph. ex Willd. (Orobanchaceae), Phytotaxa 222 (1), pp. 1-16 : 6-7

6. O. alba subsp. major (Čelak.) Zázvorka :

In addition to the subspecies treated here (subsp. cuprea, subsp. xanthostigma and subsp. alba ) a further taxon is commonly distinguished at the subspecies level, namely O. alba subsp. major ( Čelakovsky 1872: 341) Zázvorka (2000: 88) [Syn.: O. epithymum var. major Čelakovsky (1872: 341) ; O. alba f. maxima Beck (1890: 210) ]. This taxon differs from typical O. alba mainly in being larger in all parts (stem, inflorescence, flowers). Although widespread from France to Iran, it occurs mainly in the east of the total area of the species, e.g., the Caucasus region (see 4.). As host it prefers Salvia (possibly regionally exclusively so: cf. Zázvorka 2000.), but it has also been proven or at least reported as parasitizing Thymus , Acinos , Stachys recta , and Calamintha nepeta . As this taxon differs from typical O. alba only in clearly definable quantitative, but not qualitative, characters and lacks a separate distribution area, we consider the subspecific rank inappropriate. Instead, as this taxon, in its typically state, is clearly distinguishable from the nominate species, we prefer the classification on the rank of a variety.

The oldest valid name for this taxon at the rank of variety is from 1864, when Čelakovsky presented it on page 110 in the “Sitzungsberichte der königlich böhmischen Gesellschaft der Wissenschaften” as O. epithymum DeCandolle (1805: 490) var. superba Solms ex Čelakovsky (1864: 110) 1. The taxon was collected first time in July 1853 by

1.“ Die prachtvolle var. superba Solms , die nach Graf Solms bisher nur in Böhmen gefunden worden, über 1–2’ hoch, mit langer lockerblüthiger Aehre aus grossen (1” langen) lichtblaurothen und dunkler geaderten Blüthen , sammelte Winkler an der Bielalehne bei Bilin, (Juli 1853); sie soll auf Trifolium alpestre , S alvia silvestris schmarotzt haben, während die normalen Formen auf Thymus serpyllum aufsitzen.” ( Čelakovsky 1864: 110) The manuscript was submitted for the absent Čelakovský by secretary Weitenweber .

Winkler at the “Bielalehne bei Bilin” (today: Bílina, Ústí nad Labem Region, Czech Republic; see Čelakovsky 1864: 110; Čelakovsky 1872: 341 as var. β; Reuss fil 1867: 199—but here “ June 1853 ”). This name was overlooked by Beck (1890, 1930), who instead named it O. alba var. maxima . In particular, Beck (1890: 210) first listed as “4. ( Orobanche ) maxima ” although the introductory formula “Variat” designates this nomenclaturally as varietal name; he later then renamed it f. maxima ( Beck 1930: 153) . As Beck (1890) deviated from the rule of nomenclatural priority, where deemed necessary for the sake of clarity and stability, he also did not adopt the older O. epithymum var. major Čelakovsky (1872: 341) , as he considered synonymy with his var. (or later f.) maxima uncertain. The combination O. alba var. major does not exist and has been erroneously assigned by Beck (1930) to Rouy, Fl. France XI: 173. Thus, using the oldest validly published name (cf. Art. 11.4 ICBN and example 16) this variety must be named:

Orobanche alba Steph. ex Willd. subsp. alba var. superba (Solms ex Čelak.) Uhlich & Rätzel , comb. nov. (Basionym: — Orobanche epithymum DeCandolle (1805: 490) var. superba Solms ex Čelakovsky (1864: 110) .—Synonyms:— Orobanche epithymum var. major Čelakovsky (1872: 341) ; Orobanche alba var. epithymoides (Duby 1828: 349) Rouy (1909: 173) f. major (Čelakovsky) Soó (1968: 241) ; Orobanche alba var. maxima Beck (1890: 210) ; Orobanche alba f. maxima Beck (1930: 153) ; Orobanche alba subsp. major (Čelakovsky) Zázvorka (2000: 88) . Unfortunately, we were unable to find (yet) suitable type material.

The variety mainly differs from O. alba in being larger in all parts of the plant (stem, inflorescence, flowers). Casually spread from France to Iran, it occurs mainly in the east of the total area of the species. As host it prefers— according to current knowledge—namely Salvia -species (possibly regionally exclusively, cf. Zázvorka 2000.), but has also been proven or at least reported on Thymus , Acinos , Stachys recta , and Calamintha nepeta . We think this taxon to be over-ranked as a subspecies, because it differs from typical O. alba only in quantitative, but not by consistent, clearly definable characteristics and because it lacks a recognizable, separate distribution area: in the current systematics, these are essential conditions for qualifying as subspecies. Nevertheless, we believe that the taxon—in the typical developed state—is clearly distinguishable from the nominate species.