Arabis drabaeformis Boiss. in Ann. Sci. Nat., Bot. ser. 2, 17: 55. 1842.

Type: “[Aucher-Eloy] N. 100, Olympus Thessalus aut Bithynus”.

Holotypus: TURKEY: “Olymp. Bithyn.”, s.d., Aucher-Eloy 100 (G-BOIS [G00332077]; iso-: BM [BM000522055], G [G00389099, G00389279 two plants on top and one on lower left, G00389112], MPU [MPU013369], P [P00747449 plant on lower left, P00747447 four plants numbered 2 in pencil on upper half of sheet, P00747450]) .

Notes. – The above isotype G00389112, was erroneously numbered as Aucher-Eloy 160 instead of 100, and the former number is Erysimum carium (see p. 38).

The major source of confusion came from BOISSIER’s (1842a) citation of the same collection number (Aucher-Eloy 100) and exact locality data (Olympus Thessalus aut Bithynus) for both A. drabaeformis and A. bryoides . This resulted from AucherEloy’s giving the same number for the Turkish Bithynean Olympus for A. drabaeformis and Greek Thessalean Olympus for A. bryoides . Both CULLEN (1965) and STRID & TITZ (1986) realized this label mix-up.

P00747447 is a mixed collection of A. drabaeformis and A. bryoides .

Arabis drabaeformis is generally a taller plant, (7–) 10–20 cm, with much-branched loose caudex covered by some leaf remains with persistent midveins, sparsely pubescent, non-canescent basal leaves, and petals 4–6 mm long. By contrast, A. bryoides is a mat-forming plant with shorter stems 2–7(–10) cm, compact and few-branched caudex covered by persistent leaves with obscurely developed midvein, densely canescent basal leaves, and petals 6–11 mm long.