A small scene from the UBC Winter Garden in muted, cool tones; the flowering shrub in the foreground is Rhododendron moupinense, while the conifer is a cultivar of Cupressus arizonica (another cultivar of the same species, 'Blue Ice' was featured two months ago).
Agriculture resource link: Our Vegetable Travelers – “The original publication of Our Vegetable Travelers by Victor R. Boswell appeared in the August, 1949 issue, Volume 96(2) of National Geographic Magazine and is copyrighted by National Geographic Magazine. Reprinted as a special feature in the PLANTanswers section of Aggie Horticulture by permission of the National Geographic Society. February, 2000.” It's important to keep the date it was written in mind when reading about each of the vegetables, as the language occasionally reflects a different era.
Echoing Daniel's comments, although the "vegetable travelers" link contains a wealth of interesting information, much of the information (particularly on domestication) has been superseded by more recent work. For instance, the author gives the old theory of the origin of sweet corn: hybridization with Tripsacum in the South American Andes. Maize is now thought (on good evidence) to have been domesticated by simple selection from an annual teosinte (Zea mays ssp. parviglumis) in southern Mexico not more than 9,000 years ago.
See:
Matsuoka Y et al. (2002). A single domestication for maize shown by multilocus microsatellite genotyping. Proc Natl Acad Sci U S A. 99: 6080-4.
Doebley J. (2004). The genetics of maize evolution. Annu Rev Genet. 38: 37-59.
Flowering rhododendrons down here currently spoiled by frosty nights.
Like Cupressus arizonica 'Blue Ice', C. arizonica 'Silver Smoke' is a Duncan & Davies nursery of New Zealand introduction dating from 1984 or earlier, in North America by 1985.