[Illustration: Ternate Grape Fern Botrychium ternatum var. intermedium (Reduced)]
[Illustration: Ternate Grape Fern Botrychium ternatum var. intermedium (Two stocks, reduced)]
[(7) RATTLESNAKE FERN. Botrychium virginiànum]
Fronds six inches to two feet high. Sterile segment sessile above the middle of the plant, broadly triangular, thin, membranaceous, ternate. Pinnules lanceolate, deeply pinnatifid; ultimate segments oblong or lanceolate and scarcely or not at all spatulate. Fertile part long-stalked, two to three pinnate, its ultimate segments narrow arid thick, nearly opaque in dried specimens. Mature sporangia varying from dark yellow-brown to almost black. Open sporangia close again and are flattened or of a lenticular form. In rich, deciduous woods, rather common and widely distributed.
[Illustration: Rattlesnake Fern. Botrychium virginianum (From Waters's "Ferns," Henry Holt & Co.)]
Prince Edward Island, Minnesota, south to Florida and Texas, and north to Newfoundland and Labrador.
Var. grácilis. A form much reduced in size.