Botrychium simplex (Ophioglossaceae) in the Baltic countries and adjacent areas – a monographic study

Botrychium simplex is the smallest and presumably the most variable species within the genus Botrychium. In Europe, today’s B. simplex was found for the first time as early as 1823 by the pharmacist Wilhelm Kannenberg in East Prussia (near the town of Memel, now Klaipėda, Lithuania). Almost three decades later, it was described as B. kannenbergii („Kannenbergii“) by Klinsmann (1852) in honor of the finder. He was unaware of the fact that in North America this species had already been named B. simplex by E. Hitchcock in 1821. The European distribution of B. simplex is concentrated in the northern and eastern parts of the continent with a number of isolated occurrences in the higher mountains, especially in the Alps and the Pyrenees. In this paper, we give a complete overview of all previously documented and known finds of this species in the Baltic States and adjacent territories, and discuss its current status. Our study reveals a drastic decline of B. simplex populations in Eastern Europe. Only three of the 14 records from the Baltic States are from the 21st century suggesting that most of the older occurrences are extinct. We present a compilation of infraspecific names (varieties and forms) of B. simplex established in Europe and North America and discuss the taxon tenebrosum, classified partly as a species and partly as a variety. The morphological diversity of the gametophyte is illustrated. We report on the nuclear DNA content of both the sporophyte (22.98 pg/2C) and the gametophyte (11.28 pg/2C) of B. simplex. From these, a ratio of almost exactly 2 results indicating that the species reproduces sexually. This is apparently the first published value of the DNA content of a Botrychium gametophyte. Botrychium simplex has been noted for its broad ecological amplitude. We summarize data regarding abiotic (altitude, soil parameters) and biotic (vegetation types, mycorrhiza) factors that might influence species population development and longevity and provide knowledge for future species monitoring and management.

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