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afforded allied anomaly atavism atavistic bear become biennis bracts branches breeder buds characters clover color common considered constant corolla course crosses cultivated culture curious Darwin deviations double flowers doubt Draba verna elementary species evening-primrose ever-sporting evidence evolution experimental experiments facts fertilization flowering plants fluctuating forms fruits garden genera give given horticultural hybrid individuals instances intermediate isolated known lamarckiana large numbers latency latent leaves lecture limited mutability mutations nature nearly normal observed occur Oenothera offspring once ordinarily ordinary origin origin of species parents peloric petals pistillate plants pollen produced pure qualities race racemes rare remain result retrograde retrograde varieties reversion rieties rule seedlings seeds seen selection shepherd's purse single sowed species and varieties specimens spikes sport stamens stances stems strain striped subspecies systematic species tion true units variability varie varietal Viola tricolor wheat white variety whole wholly widely wild yellow
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 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.