Species and Varieties, Their Origin by Mutation: Lectures Delivered at the University of California

Front Cover
Open court publishing Company, 1905 - Evolution - 847 pages
0 Reviews

What people are saying - Write a review

We haven't found any reviews in the usual places.

Other editions - View all

Common terms and phrases

Popular passages

Page ix - My work claims to be in full accord with the principles laid down by Darwin and to give a thorough and sharp analysis to some of the ideas of variability, inheritance, selection, and mutation which were necessarily vague in his time.
Page 853 - Cloth, $1.50 net (6s. 6d. net). BINET, ALFRED. THE PSYCHOLOGY OF REASONING. Pp. 193. Cloth, 75c net (3s. 6d.). THE PSYCHIC LIFE OF MICRO-ORGANISMS. Pp. 135. Cloth, 75c (3s.
Page 689 - This conception led to the expectation of two different kinds of variability, one slow and one sudden.
Page 851 - Cloth, $1.50 (7s. 6d.). POWELL, JW TRUTH AND ERROR ; or, the Science of Intellection. Pp. 423. Cloth, $1.75 (7s.
Page 527 - The leaves of the original form show numerous sinuosities in their blades, not at the edge, but anywhere between the veins. The blade shows numbers of convexities on either surface, the whole surface being undulated in this manner; it lacks also the brightness of the ordinary evening-primrose or Oenothera biennis. These undulations are lacking or at least very rare on the leaves of the new laevifolia. Ordinarily they are wholly wanting, but at times single leaves with slight manifestations of this...
Page 851 - Cloth, $1.50 net (5s. 6d. net). SCHUBERT, HERMANN. MATHEMATICAL ESSAYS AND RECREATIONS. Pp. 149. Cuts, 37. Cloth, 75c net (3s. net). HUC AND GABET, MM. TRAVELS IN TARTARY, THIBET AND CHINA.
Page 460 - ... at times new qualities and at other times leaving the plants unchanged during long successions of generations. All lines of the genealogic tree show alternating mutating and constant species. Some lines may be mutating at the present moment; others may momentarily be constant. ... In a complete and systematic enumeration of the real units of nature, the elementary species and varieties are thus observed to be discontinuous and separated by definite gaps.
Page 66 - ... processes of descent and reveal their degenerate state. Sometimes the removal of selected varieties to new conditions calls forth large numbers of degenerative variations, and sometimes a notable change occurs in a whole planting as though a simultaneous mutation of all the individuals had taken place.1 Wide variability is the most efficient means of acclimatization, and only species with many elementary units would have offered the adequate material for Introduction into new countries. * * •...
Page 525 - Both the stems and the rosettes were at once seen to be highly variable, and soon distinct varieties could be distinguished among them. The first discovery of this locality was made in 1886. Afterwards I visited it many times, often weekly or even daily during the first few years, and always at least once a year up to the present time. This stately plant showed the long-sought peculiarity of producing a number of new species every year. Some of them were observed directly on the field, either as...
Page 532 - Nanella is a dwarf plant, but it is not distinguished by its smaller size alone. From its first leaves to the rosette period, and through this to the lengthening stem, the dwarfs are easily distinguished from any other of its congeners. The most remarkable feature is the shape of the leaves. They are broader and shorter, and especially at the base they are broadened in such a way as to become apparently sessile. The stalk is very brittle, and any rough treatment may cause the leaves to break off.

Bibliographic information