Carex ×helenae hybr. nov. [= Carex demissa × C. oederi, Cyperaceae], in the Netherlands

The genus Carex (Cyperaceae) counts over thirty hybrids in the Netherlands, of which the hybrid of Carex demissa and C. oederi is the only one as yet within the hybrids of Carex section Ceratocystis occurring in the Netherlands without a binomial name. Therefore, this hybrid has been provided here with the name Carex ×helenae and its holotype has been selected as well. Where both parental species grow together, the hybrid can often be found as well. In all its features it is intermediate to the parents.