Hieracium heldreichii, Boissier, 1856

Szeląg, Zbigniew, 2018, Hieracia balcanica XV. Taxonomic and nomenclatural notes on Hieracium pilosissimum and H. divaricatum, with remarks on the H. heldreichii aggregate (Asteraceae), Phytotaxa 356 (1), pp. 81-90 : 87

The Hieracium heldreichii aggregate

The hybridogenous taxa between the H. pannosum agg. and H. racemosum agg. are common in the Balkan Peninsula and in Asia Minor. Zahn (1938) included these taxa into two aggregates; the H. heldreichii agg. comprising taxa of the morphological formula H. pannosum < H. racemosum , and the H. pilosissimum agg. comprising taxa of the morphological formula H. pannosum ≥ H. racemosum . This separation is arbitrary and has unfortunately consequences: (1) H. koenigianum (Zahn) Üksip in Schischkin & Bobrov (1960: 200) is morphologically closer to H. racemosum , but Zahn placed it into the H. pilosissimum agg., (2) Hieracium thessalum Formánek (1896: 292) shows a combination of morphological characteristics of H. pannosum s. lat. and H. sparsum Frivaldszky (1836: 436) , and belongs to the H. jankae agg. (see below).

As mentioned above, the use of the name H. pilosissimum agg. for the hybridogenous taxa between the H. pannosum agg. and H. racemosum agg. is incorrect. That is why I propose to include the following taxa, formerly placed by Zahn (1938) in the H. pilosissimum agg., into the H. heldreichii aggregate, which is based on H. heldreichii Boissier (1856: 102) .