International Succulent Introductions (ISI) is the plant distribution program of the Huntington Botanical Gardens, a private institution with a world-renowned Desert Garden. The ISI program has had a long-standing association with The Huntington since shortly after its inception in 1958. The program was adopted in its entirety by The Huntington in 1989 and furthers the institution's dedication to aesthetics, education, conservation, and scientific study. The aim of International Succulent Introductions is to propagate and distribute new or rare succulents to collectors, nurseries, and institutions. In keeping with sound conservation practices, field-collected plants are not sold. We offer only propagated seedlings, grafts, tissue-cultured plants and rooted cuttings produced under nursery conditions without detriment to wild populations. Income is used solely to support this program. An annual mail-order offering appears in the Cactus and Succulent Journal. The Huntington is a not-for-profit, 501(c)(3) organization. Charitable contributions to the Huntington's ISI program are welcome.
The saguaro cactus (Carnegiea gigantea Britton and Rose) is a large columnar species that is a defining and keystone plant in the Sonoran Desert of the southwestern United States and northwestern Mexico. There has been a long history of study of the saguaro cactus, yet many gaps remain in our knowledge of the species, including details of seed dispersal mechanisms and recruitment success. Effective dispersal of saguaro seeds is essential for recruitment and persistence of the plants, and a variety of bird and mammal species are known to contribute to this process. Recent observations of frugivory and saguaro seed dispersal by the Common Raven (Corvus corax Linnaeus 1758) are reported here for the first time. The Common Raven is added to the list of endozoochorous animals that feed on saguaro fruits and is a potentially effective seed disperser for these plants. Seed dispersal by the birds is confirmed by aerial excretion, the seed shadow pattern matching the clustered establishment of same age saguaros commonly observed beneath nurse plants. We consolidate saguaro seed disperser records from the literature and discuss saguaro seed dispersal mechanisms. Our observations show the Common Raven as a consumer of the fruit and seed disperser of the saguaro cactus, bringing the total of known saguaro seed dispersing animals to 53 species. Due to the size of the birds, they are potentially capable of moving large numbers of seeds over greater distances than smaller birds and small mammals and may be one of the more important animals performing this service.
