This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
(Greek name of saffron). Iridaceae. Low spring-flowering and autumn-flowering garden bulbs; showy, and well known.
Stemless plants (the grass-like leaves rising from the ground or corm), with solid bulbs or corms: flowers showy, in many colors, funnel-shaped and erect, with a very long tube and 6 nearly or quite equal segments; stamens 3, attached in the throat of the perianth and shorter than the segments; style 3-cleft, the branches entire or forked or much fimbriated; ovary 3-loculed: seeds many, nearly globular: fruit an oblong 3-valved caps. - Probably 75 species, many of them variable, in the Medit. region and extending into S. W. Asia. The flowers open in sunshine. They come in fall or spring, but the best-known species are spring-flowering, which are amongst the earliest and brightest of spring bloom. Crocuses force easily (see Bulb). A half-dozen corms may be planted in a 4-in. pot for this purpose. Crocuses are scarcely known in the American trade under their species names. Inasmuch as the flowers of the common crocus close when taken out of the sun, they are not popular as window-garden or house subjects. Crocuses have been much hybridized and varied. There are many color-forms. The common crocuses of the trade have descended from C. vermis chiefly, but C. susianus, C. moesiacus, C. stellaris, C. biflorus and C. sativus are frequent.
The Dutch bulb-growers cult, many species, and these are offered for sale in their American lists; the species are therefore included in the following synopsis. In this account, the treatment by Baker is followed (Handbook of the Irideae).
Botanically, the genus divides itself into three groups on the characters of the style-branches: the branches entire, once-forked or fimbriated at the apex, or cut into several capillary divisions. Horticulturally, the species fall into two groups,-the spring-flowering and the autumn-flowering. These groups are not so definitely separated as it would seem, however. Some of the species bloom in winter in regions in which the ground does not freeze hard; others begin to bloom in July or August; some may continue to bloom till winter closes in. Yet these two flowering periods mark very important differences in the utilization of the plants and the primary division in the following treatment is made on this basis. The colors are now much varied by cultivation and hybridizing, but they are well marked in the specific types as a rule. They run largely in yellow, white and purple.
The covering or tunic of the bulbs may be uniformly membranaceous, or it may be composed of strongly reticulated or parallel fibers. Fig. 1113. The flowers appear usually just in advance of the grass-like foliage-leaves. The floral leaves are small and more or less dry or scarious and arise directly from the corm and may be seen as a spathe-like structure inside the leaf-tuft; this is usually known as the basal spathe. The real spathe subtends the bloom, and it is always one-flowered; this floral spathe may be one-leaved or two-leaved.
Fig. 1113. Reticulated and membranaceous tunics. Crocus susianus (left) and C. sativus (right).