CYTOLOGICAL AND CHEMICAL VARIATION IN PITYROGRAMMA TRIANGULARIS

A B S T R A C T The cytology and chemistry of three populations of the species complex Pityrogranima triangularis from Santa Barbara County, California, were studied. The basic chromosome nutmber of these ferns is x = 30, and there are diploids, triploids, and tetraploids. Although gross morphology in the plants is similar, four chemical types are observed when extracts of the external frond pigments are analyzed. Ten of the twelve possible combinations of ploidy level and pigment types have been found. Correlations of spore condition, cytology, and chemistry which indicate either an autotetraploid or allotetraploid derivation of the complex are discussed. THE GOLD-BACKED and silver-backed ferns of western North America constitute a complex, commonly treated taxonomically as a single species, Pityrogramma triangularis (Kaulf.) Maxon, which extends from British Columbia south to Baja California and eastward in the southern part of its range into Arizona. The greatest abundance and variation are encountered in the coastal mountains of southern California. Depending upon local environmental conditions, plants may be inconspicuous dwarfs a few centimeters tall, or robust individuals several decimeters in height. The smallest individuals grow in exposed areas, while the largest are found in the shade and along moist banks. The fronds are deeply cleft into numerous divisions and the whole outline tends to