During the early 1950's there appeared reports, from time to time of the presence among the products elaborated by actinomycetes of antifungal antibiotics which exhibited very similar and very characteristic multipeaked ultraviolet absorption spectra. In 1954, with a good number of examples on record, these spectra were analyzed and identified as those of straight-chain conjugated polyenes, comprising tetraenes, pentaenes, hexaenes and heptaenes (85, I30). These antibiotics have since been commonly referred to as the polyene antifungal antibiotics to distinguish them from a host of other...

In their monumental work "The Cactaceae," BRITTON and ROSE (I9) record 1235 species belonging to the three tribes which constitute the family of the Cacti. The actual number of the species must be con siderably higher. Cacti occur frequently in tlie more arid and less accessible regions of the American Continent, nearly always within very narrow and definite borderlines. The habitat of a species is in many instances a single valley located in a remote, uninhabited region of the Cordillera. Thus the collection of flowering specimens fit for botanical identification is some times extremely...