A new Arum species (Areae, Araceae) from NE Turkey and Georgia

In 1990, Manfred Koenen, then horticulturist at the Botanic Gardens Bonn, collected rhizomes from an Arum in a remote area of NE Turkey. Being aware that this might turn out to be an interesting collection, one year later Mr Koenen returned to the area and was able to collect more material.
When the plants flowered a few years later in the Botanic Gardens Bonn, the first two authors were not sure about its identity. Knowing that Peter Boyce was then working on a monograph on the genus Arum, we wanted to wait until the book was published. However, by certain circumstances, we lost the potential new species from our minds. In 2003, Andreas Gröger from Munich, the first author and Zurab Schewardnadse from Tblissi were collecting plants in Georgia. Among other material, an Arum was collected and brought to the Botanic Gardens Bonn. It flowered in 2004, at which point we realized that it was the same species as the material gathered more than ten years earlier by M. Koenen. Having compared our plants with the Arum monograph by Boyce (1993), it appeared rather certain that it represents an undescribed taxon. Adding the expertise of the last two authors, it is here described as a new species of A. subg. Arum.
As currently defined, Arum comprises 28 species (Boyce 1993, 1996, 2006), although, as noted by Boyce (2006), much remains to be done before it can be claimed that Arum is well understood. The recognition of a new species in the taxonomically difficult A. subg. Arum may well seem a taxonomically risky step but at this time we cannot fit this clearly distinct plant into any of the currently recognized species and thus it seems useful to give it formal recognition with the caveat that at some future date a critical revision may well result in changes to its taxonomic status.