Friday 2 August 2013

A new species of Hawkweed from Bulgaria.

Hawkweeds (Hieracium spp.) are herbaceous flowering plants in the Aster Family (Asteraceae), closely related to Dandelions. There are numerous species in Europe, Africa, Asia, and North and South America, though the precise number of species is open to dispute, as most Hawkweeds are triploid (have three sets of chromosomes, which means that they cannot reproduce sexually (which requires an even number of chromosomes sets, which can then divide and recombine); the plants instead produce seeds asexually that are genetically identical to the parent plant. These triploid species are thought to have arisen by hybridization of diploid species (i.e. species with two sets of chromosomes that can reproduce sexually). This has led to some dispute over the classification of Hawkweeds, with American botanists tending to regard only the diploid, sexual, species as truly valid taxa with other plats regarded as hybrids of these, while in Europe botanists have tended to recognize the triploid, asexual, varieties as species as well, arguing that they may be of hybrid origin, and incapable of reproducing sexually, but are clearly successful organisms capable of sustaining large stable populations and competing against diploid plants.

In a paper published in the journal Phytotaxa on 20 May 2013, Zbigniew Szeląg of the Institute of Botany at Jagiellonian University, and Vladimir Vladimirov of the Department of Plant and Fungal Diversity and Resources at the Institute of Biodiversity and Ecosystem Research at the Bulgarian Academy of Sciences, describe a new species of Hawkweed from the central Rhodopes Mountains of southern Bulgaria.

Specimen of Hieracium crinitopannosum from by the road from Devin town to Mihalkovo village in the central Rhodopes Mountains of southern Bulgaria. Szeląg & Vladimirov (2013).

The new species is named Hieracium crinitopannosum; it is thought to be a hybrid between Hieracium crinitum and Hieracium petrovae, two diploid species found in the Rhodopes Mountains (Hieracium petrovae) and nearby Vacha River valley (Hieracium crinitum). Hieracium crinitopannosum is a 25-55 cm robust Hawkweed that flowers (pointlessly) in July and August and sets seeds in September. It is found growing in open spaces on eroded and rocky slopes in stands of a several dozen to a few hundred in the central Rhodopes Mountains of southern Bulgaria; Szeląg & Vladimirov suggest that it is likely that it is also found across the border in northern Greece.

The approximate location of the area where Hieracium crinitopannosum was discovered. Google Maps.

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