The Occurrence of Mecodium wrightii in Canada

Abstract

I have recently received from Mr. C. V. Morton a notice of the occurrence of an interesting filmy fern in British Columbia. Complying with my request, he kindly lent me the specimen in the United States National Herbarium, and suggested that I should prepare a note on it. The specimen examined is labelled as Mecodium wrightii, an identification of E. B. Copeland, It was collected by Dr. H. Persson in Canada in the summer of 1957, the locality being: North end of Dawson Inlet, off Skidegate Channel, Graham Island, Queen Charlotte Islands, British Columbia, on west exposed shady vertical precipice, ca. 10 m.s.m. There is no question that this filmy fern is Mecodium wrightii (v. d. Bosch) Copeland. Mecodium iwrightii was originally described by van den Bosch1 on the basis of a specimen collected by C. Wright at Hakodate, in Hokkaido. The known range of distribution has been from Saghalien2 and the southern Kuriles3 to Kyushu and southern Korea. The headquarters of its distribution lie in the central and northern districts of Honshu, usually at altitudes lower than 11500 meters. In Shikoku and Kyushu it is found, rarely, at 500 to 1000 meters elevations. In the regions where M. wrightii is most abundantly found, it is usually growing on the bases of the trunks of large trees, especially of aged Cryptomeria japonica (Pl. 8, 9), in humid dense mountain forests. These substrata are in general moist and mossy. In northern Honshu and Hokkaido, it grows mostly on mossy rocks or cliffs in shade and usually in places with high humidity. Viewed in the vertical distribution, it grows, even in Hokkaido, at altitudes higher than 1000 meters, but it has never been collected in the alpine regions of central Honshu, where M. polyanthos is occasionally found. Thus, M. wrightii has more limited habitats and distri-