Staurastrum echinatum Ralfs (1848: 215)

Staurastrum echinatum Ralfs (1848: 215) ( Figs. 1 View FIGURES 1–7 , 22–25 View FIGURES 22–29 )

Staurastrum echinatum , published by Ralfs (1848) on the basis of drawings made by Alphonse de Brébisson, is a rather rare, spiny Staurastrum that in former times repeatedly was confused with other species. This was mainly due to Ralfs’ extremely concise description. It was Heimans (1926) who, examining Brébisson’s original exsiccata, provided a much more detailed characterization of this species rendering reliable identification a lot easier. So far, no zygospores were known of St. echinatum ( Coesel & Meesters 2013) . The zygospore attributed to this species by Grönblad (1920, pl. 1: 38–40) clearly refers to an other species, presumably Staurastrum teliferum Ralfs (1848: 128) .

In the Dutch province of Drenthe, St. echinatum ( Figs. 22, 23 View FIGURES 22–29 ) is less rare than elsewhere in the Netherlands. In some samples it was even of abundant occurrence, e.g. in a sample originating from military training area ‘De Haar’, collected 5 January 2013. It was in this sample that we encountered some conjugating specimens. The zygospores may be characterized as about globose and provided with stout protuberances. Those protuberances are conical, passing into a spine that is repeatedly bi- or threefold truncate ( Figs. 1 View FIGURES 1–7 , 24, 25 View FIGURES 22–29 ).