National Geographic : 1925 May
THE NATIONAL GEOGRAPHIC MAGAZINE y, ,,t . ' . v. S-s <~ *<** Frond two-thirds natural size © Painting by E. J. Geske RATTLESNAKE FERN (Botrychium virginianum) This belongs to a family (Ophioglossaceae) quite unlike the "true ferns " in structure and in methods of spore production. Surmounting the lacy sterile blade is a long-stalked "fruiting" panicle, from which the powdery, pale sulphur-yellow spores are shed in the utmost profusion. A cluster of partly open, purselike sporangia is shown above, magnified about 45 times. After the spores are shed both stalk and sporangia shrivel and nearly disappear.