National Geographic : 1947 Jul
Mexico, Happy Hunting Ground for Botanists IN A lower corner of the opposite page our artist has shown the typical home of a Zapotecan Indian surrounded by its living cactus fence. This is not just any house; it is in the State of Oaxaca in southern Mexico in the little village of Mitla. It was from Mitla some years ago that Goopar, my Zapo tecan friend and companion, and I set out on a journey to the great mountain called Zem poaltepec; it was to Mitla and his home that we returned weeks later, our pack-mules laden with pressed museum specimens, living plants, and seeds. If by some curious chance Goopar should see this picture he, too, will recall the incident of the Poinsettia bush which grew beside his house. But that is a story much too long to tell here; besides, the joke concerns only Goopar and me-and a certain old fool of a cargo mule. COSMOS: The genus Cosmos, with about 20 species, is entirely tropical American. The two species most frequently grown in our gardens are both Mexican. The more common of these is Cosmos bipinnatus,well known in its various crimson, pink, and white forms. The other species, less common, is Cosmos sulphureus, which, as its specific name would indicate, has yellow flowers. Today apparent hybrid garden forms exist, but the true C. sulphureus is easily recognized by having somewhat longer central (disc) flowers with their dark colored stamens sticking out farther than those of C. bipin natus. I have often thought it a pity that gardeners, especially those in the north, nowadays rarely see the Cosmos in its full splendor. Recently a friend of mine boasted how, at last, he had learned to "handle" his Cosmos so that they didn't "get out of hand." I saw his plants and they were miserable, spindly things less than two feet high, with scarcely a half dozen blooms on any plant open at the same time. Being a little old-fashioned, perhaps, I would start mine earlier in the season, grow them in well enriched soil so that by late summer the plants would be wide-branched and not less than six feet tall. If "handled" properly some times they can be forced to as much as ten feet. Grown thus, they will ordinarily be covered with as many as a hundred blooms at once. Cosmos, naturally, are not suited for low bed ding purposes in the garden, and anybody who tries to treat them thus robs himself of the magnificent show which this group of gay and colorful plants can produce. ZINNIA (Zinnia elegans): The wild material of this well-known garden plant has rather uninteresting dull-purplish blooms; in this form they were first introduced into European and American gardens, as the early pictures show. What has happened since is a living monument to the science-one is here impelled also to say the "art"-of the hybridist and selector for, as Dr. L. H. Bailey, revered dean of American horticulture, has pungently re marked, they now are "of nearly every color except blue and green." I strongly suspect that another Mexican species, Zinnia Haageana, through hybridiza tion, has contributed something in the way of red and orange to the color forms of elegans. This latter species, usually more dwarf and with smaller blooms than elegans, is also of fered by many seedsmen in various colors and shapes. Like the Cosmos, Dahlia, Daisy, and various other kinds included in this series, the Zinnia belongs to the Sunflower Family, or Composi tae. If one examines the "flower" of a Zinnia carefully, it will be noted that actually it is not a single flower. In the wild, or "single," forms there generally are two types of flowers pres ent, the inner or "disc" flowers and the outer, highly modified and petal-like "ray" flowers. In the Zinnia, as in other members of this family, the so-called "double" forms are merely those in which the disc flowers have taken on the characteristics of the ray flowers. This may readily be seen by examining one of the "half-double" types. Various types of garden Zinnias are shown in the accompanying pic ture. Sometimes in an unnamed "mixture" a plant with flowers like the one farthest to the right will appear. Such plants are "throw backs" which approach the wild type. POINSETTIA (Euphorbia pulcherrima): In our high school Latin class probably one of the first adjectives we learned was pulcher-mean ing "beautiful" or "handsome." Later we also learned that the Romans had intensifiers which they tacked on to their adjectives. Thus it was that when the old botanist Karl Ludwig Will denow was searching for a suitable name for his new species of Euphorbia about 150 years ago-and scientific botanical names are in Latin, or a Latinized form of Greek-he scarcely could avoid calling it "the very beau tiful Euphorbia," or Euphorbia pulcherrima. In the discussion of another species of this genus, the Crown-of-Thorns from Madagascar (pages 38, 39), it was noted that the bright scarlet objects which make the Poinsettia of Mexico so handsome actually are not parts of the flower; instead, they are highly modified petal-like leaves,which the botanist calls bracts.