Panicum capillare L. (Draadgierst) en Panicum barbipulvinatum Nash in Nederland: eerherstel voor een miskende soort

Panicum capillare L. (Draadgierst) and Panicum barbipulvinatum Nash in the Netherlands: rehabilitation for a misidentified species Panicum capillare belongs to a group of closely related and badly known species. One of these, P. riparium H.Scholz, was suspected to be a neo-indigenous species for Europe that has evolved from P. capillare, but was recently recognized by Amarell as actually being P. barbipulvinatum Nash, which is indigenous to the United States. To evaluate the diagnostic value of morphological characters, the authors decided to measure a set of flower features of all specimens of P. capillare s.l. in the herbarium collections of Naturalis Biodiversity Center and the Natural History Museum Nijmegen. Their study showed that (i) with some practice, P. barbipulvinatum and P. capillare are easily distinguished; (ii) P. barbipulvinatum arrived in the Netherlands over more than hundred years ago; (iii) P. barbipulvinatum is even more abundant than the well-known and cultivated P. capillare. Panicum hillmannii Chase, often treated as a subspecies of P. capillare, appeared to be the most neglected taxon.