leaves that are velvety to the touch make it a striking and easy to recognize plant. In 2007, it was observed at an abandoned coal mining site in Hensies. An earlier Belgian record for Brussels (Jean 1975) now appears to be referable to O. oakesiana. Just as with Oenothera canovirens, O. depressa easily forms hybrids with species from the series Oenothera and Rugglesia. At a coal mining spoil heap in Beringen-Mijn
Figure 8. Oenothera deflexa. Zwijnaarde (Gent), roadside, August 2014. This species is recognized by its small-sized petals and the absence of hairs with a red bulbous base.
whereas in Sweden its occurrence was considered as very rare. According to field observations carried out by the second author, it is also to be found in the Netherlands and France, close to the Belgian frontiers. At a sand storage area in the canal zone of Bruges, a hybrid with Oenothera fallax has also been found growing among the parental species. Likewise, in the port of Bruges and at several other locations, putative (unstabilized) hybrids of this species with O. biennis have also been collected. • Oenothera depressa E. Greene, Pittonia 2: 216. 1891. = O. hungarica (Borbás) Borbás, Magyar Bot. Lapok 2: 246. 1903. = O. salicifolia Desf. ex G. Don, Gen. Hist. 2: 685. 1832, nom. inval. Figure 9. Probable area of origin: North America. This species belongs, just as Oenothera canovirens, to the characteristic series Devriesia (see earlier). It differs mostly from the latter by the striking wavy edges of the leaves and bracts, the presence of numerous hairs with a red-bulbous base and the usually cleistogamous flowers. This combination of characteristics as well as the numerous white, eglandular hairs on the young fruits and the
Figure 9. Oenothera depressa. Hensies (Les Sartis), abandoned coal mining site, July 2007. This species is softly grey-hairy throughout, its leaves have wavy margins and flowers are often cleistogamous.
K. Rostański and F. Verloove, The genus Oenothera in Belgium [Dumortiera 106/2015: 12-42]
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