Book Description

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913. Excerpt: ... cultivated wheat was seen in the flowering stage. A few days before several spontaneous plants of domesticated wheat had been seen near El Hadr with many exserted anthers. The plants that showed the open glumes were vigorous individuals, growing close to an irrigation ditch. Both plants belonged to the same general type, which may be considered as a primitive form of the domesticated species in view of the apparent retention of the habit of cross-fertilization. The glumes of the domesticated wheat were open early in the morning, as in the wild wheat. In a recent report on the crossing of wheat in India the suggestion is made that cross-fertilization takes place when the glumes are opened by the wilting of the plants in the middle of the day.1 ADAPTATIONS FOB DISSEMINATION AND GEBMINATION. STRUCTURE OP RACHIS AND SPIKELETS. Though domesticated plants are superior to wild species from the standpoint of utility to man, this superiority often involves a loss of some of the specialized characters that were of use to the plants in the wild state. From a biological viewpoint the wild wheat appears superior to the domesticated plant in its adaptations for protection and sowing of the seed, as well as in its better provision for crossfertilization. In the discussion of cereals from the agricultural standpoint the difference between the heads of wheat and barley is usually described by saying that barley has a fragile or brittle rachis, but this expression seems inadequate to describe the fact for biological purposes. The rachis of the wild wheat as well as of wild barley is not merely brittle in the sense of being broken easily, but is provided with 1 "It will be evident from the above that natural crossing in wheat is far more frequent under the conditions obtain...