133 



For example, one learns that the generic name Amaryllis is pre- 

 ferred to the name Hippcastrum and that the species name Hemer- 

 ocallis Thiinbergii is approved instead of the name Hemerocallis 

 serotina. In respect to the standardization of scientific names the 

 volume should be of value to gardeners and nurserymen. 



In recognizing the clone and the polybrid the Editorial Com- 

 mittee of Standardised Plant Names renders a somewhat belated 

 service to both botany and horticulture. In the first edition these 

 distinctions were not made. That the rules of botanical nomenclature 

 adopted to date are inadequate in application to cultivated plants 

 has been noted in various publications and also in the deliberations 

 and recommendations of the International Committee for Horticul- 

 tural Nomenclature. 



It has long been recognized that all members of a clone have 

 collectively only the status of an individual. Methods of vegetative 

 propogation, especially for perennial plants, have made the clone 

 an important and very general horticultural unit. The term "clon" 

 was proposed in 1903 but recently most writers have used the 

 spelling "clone." The Editorial Committee of Standardised Plant 

 Names wishes to give the spelling that was first proposed prefer- 

 ence over that in recent general usage; but does not hesitate to 

 ofifer many new changes in the spelling and the pronunciation of 

 other terms. 



The heterogenic nature of many groups of cultivated plants has 

 been emphasized by genetical studies as well as by the experiences 

 of gardeners. Often this condition arises after hybridization but it 

 is more or less developed in the population of any species. If seed- 

 reproduction is the rule for a group of hybrids, as in Petunia, there 

 is usually segregation into true-breeding varieties each of which de- 

 serves a distinctive name. But for most perennial plants the polybrid 

 group is soon separated into clones each of which deserves a clonal 

 name. In horticulture a polybrid group is a rather temporary and 

 variable group in comparison to the clone. 



The horticultural varieties grown from seed are not listed in 

 Standardised Plant 'Names for certain genera; as, for example, 

 Petunia and Zinnia. But extensive lists of seed-grown varieties are 

 given for barley, oats, flax, rye, wheat, sorghum, and other agricul- 

 tural plants. 



