Cultivars are without rank in the hierarchy of 

 botanical nomenclature. In woody plants, culti- 

 vars are usually perpetuated as clones, that is as 

 a genetically uniform assemblage of plants 

 derived originally from a single individual and 

 reproduced asexually as cuttings, divisions, or 

 grafts, or by obligate apomixis. Seed-reproduced 

 cultivars occur infrequently among woody plants 

 (for example, in Acer and Betula). They are, 

 however, well known in herbaceous genera, for 

 example, Impatiens, Phlox drummondii 

 'Sternenzauber', and Zea mays. 



Cultivar names, to be legitimate, must be regis- 

 tered through the appropriate international 

 registration authority or published with an 

 adequate description in a recognized publication, 

 such as a dated nursery catalog or journal. 

 Cultivar names simply listed in a nursery catalog 

 or other publication are without valid status. 

 These practices are important for ensuring the 

 validity and stability of cultivar names. Cultivar 

 names published on or after January 1, 1959, 

 may no longer be in Latin form but must be 

 fancy names in the vernacular, that is, in English 

 or another modern language. Cultivar names 

 may be designated by the abbreviation cv. pre- 

 ceding the name, or, as in this catalog, by single 

 quotation marks as in the following examples: 

 Abelia 'Edward Goucher', Hibiscus syriacus 

 'Diana', and Magnolia 'Galaxy'. However, cultivar 

 names in Latin form published before January 1 , 

 1959, such as Acer palmatum 'Atropurpureum' 

 and Ilex aquijolium 'Argentea Marginata', must be 

 retained, according to the Cultivated Code. 



Our method of listing cultivar names alphabeti- 

 cally facilitates easy identification of the binary 

 name (Latin scientific name) associated with a 

 cultivar name, especially in those genera for 

 which the user of the catalog does not know the 

 species of a particular cultivar. The following 

 examples from the genus Acer illustrate the 

 usual method of citing cultivars, first listing the 

 cultivar name and, in square brackets, identify- 

 ing the species: 'Akaji Nishikf [A. palmatum 

 Thunb. ex J.A. Murr.]; 'Schwedleri' [A. 

 platanoides L.]; and Temple's Upright' [A. 

 saccharum Marsh.). In some cases, the cultivar 

 is identified only as to genus. 



Sexual hybrids 



In interspecific hybrids, a multiplication sign is 

 placed before the hybrid epithet as in Abelia 

 Xgrandiflora, a hybrid of A. chinensis and A. 

 untflora. In intergeneric hybrids, a multiplication 

 sign is placed in front of the hybrid genus name 

 as in x Cupressocyparis leylandii, a hybrid of 

 Chamaecyparis nootkatensis and Cupressus 

 macrocarpa. 



Graft chimeras 



As defined in the Cultivated Code, "Graft-chimae- 

 ras are composed of tissues in intimate associa- 

 tion from two different plants. They originate by 

 grafting and are not sexual hybrids." There is no 

 combining of cell contents or nuclei as in the 

 case of hybrids; thus the word hybrid is inappro- 

 priate for these plants. In a graft chimera, the 

 tissue of a shoot originating at the callus of the 

 graft union contains at least one cell from the 

 scion and one from the root stock. Periclinal 

 chimeras, in which cells from the scion and cells 

 from the stock are in different layers, are persis- 

 tent when propagated. Chimeras may exhibit 

 characters typical of the scion or the stock, or a 

 range of intermediate forms. 



The graft chimeras listed in the catalog are of 

 the periclinal type. Graft chimeras are most 

 unusual in the simultaneous production of 

 flowers from the scion and from the stock. They 

 are known worldwide by only a very few well- 

 documented examples; two are listed in the 

 catalog, designated with a plus (+) sign before the 

 name, as follows: 



• Camellia +'Daisy Eagleson' = C. sasanqua 

 'Maiden's Blush' + C.japonica. Camellia 

 sasanqua 'Maiden's Blush' is the rootstock and 

 C.japonica, the scion. At flowering time, this 

 evergreen shrub displays simultaneously on 

 different branches the single flowers of C. 

 sasanqua and the semi-double flowers of C. 



japonica. 



• +Laburnocytisus adamii = Cytisus purpureus + 

 Laburnum anagyroides. This small deciduous 

 tree combines species of two genera of the bean 

 family (Fabaceae). Branches of the yellow flowers 

 of L. anagyroides and the dull purple flowers of 

 C. purpureus bloom simultaneously on the same 

 plant. 



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