By Cybil R Franz

Botrychium, commonly called the grape fern, is one of the genera of the order Opioglossales. It is a Eusporangiate fern family consisting of 5 to 10 species that appear to be morphologically the same but are said to be genetically different. This morphological similarity can make it difficult to distinguish the different species, characteristics may not be easy to determine. Its distribution is widespread in the north temperate region. As an herbaceous perennial, it produces a single leaf consisting of two parts; a fertile part and vegetative portion. In Botrychium, both parts of the leaf are deeply pinnately dissected in much the same way. The leaf is glabrous (smooth) but some may have simple hairs, the veins are forked throughout. It does not have circinate venation like most ferns. The outermost part of the fertile segments has 2 rows of eusporangia. The gametophytes of Botrychium are subterranean, tuberous, elongate structures with numerous rhizoids, associated with endophytic fungi. Botrychium is the only fern that produces secondary growth. The gametophytes have a dorsal ridge in which the anteridia are usually embedded along and the archegonia are found along the sides of the ridge. There is no well-established fossil record before 50 million years ago, this and botrychium being quite distinct from other living ferns show that they are an early diverging group.

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