There is a 18th century species that has been described from cultivation. The author also cited an old collector of whom he had a specimen in his own collection (the only clearly original specimen in his collection, I checked all of them). The species author's collection is now deposited in an herbarium. However, it turns out that the name has been lectotypified but the lectotype is placed to a different herbarium, which, most likely has never been visited by the species author.
Of course, lectotypification must be followed, except for the case that "the holotype or, in the case of a neotype, any of the original material is rediscovered" (Art. 9.17). If there is only one specimen (remaining) in the species author's collection, can it (1) be regarded as holotype and therefore must supersede the lectotype or (2) is the lectotypification superseded because a collection of a higher rank is available or (3) is the published lectotypification to be followed anyway?