Caro Rolando,
mi sono preso un po' di tempo ma alla fine come promesso ecco di seguito la risposta. Questi sono i primi tre articoli (di 12) del Codice Internazionale di Nomenclatura Botanica inerenti alla nomenclatura degli ibridi! Per quanto riguarda l'ordine alfabetico vedi la Raccomandazione dell'articolo 2, in cui si dice che:
"
In una formula ibrida è solitamente preferibile mettere i nomi in ordine alfabetico. La direzione dell'incrocio può essere indicata nella formula usando i simboli sessuali (C: femmina; ×: maschio) o mettendo per primo il genitore di sesso femminile. Se la sequenza non è in ordine alfabetico, il senso dovrebbe essere chiaramente indicato".
APPENDIX I
NAMES OF HYBRIDS
Article 1
1.1. Hybridity is indicated by the use of the
multiplication sign × or by the addition of the prefix "notho-" 1 to the term denoting the rank of the taxon.
Article 2
2.1. A hybrid between named taxa may be indicated by placing the multiplication sign between the names of the taxa; the whole expression is then called a
hybrid formula.
Ex. 1. Agrostis L. . × Polypogon Desf.; Agrostis stolonifera L. × Polypogon monspeliensis (L.) Desf.; Salix aurita L. × S. caprea L.; Mentha aquatica L. × M. arvensis L. × M. spicata L.; Polypodium vulgare subsp. prionodes (Asch.) Rothm. × subsp. vulgare; Tilletia caries (Bjerk.) Tul. × T. foetida (Wallr.) Liro.Recommendation 2A
2A.1. It is usually preferable to place the names or epithets in a formula in
alphabetical order. The direction of a cross may be indicated by including the sexual symbols (C: female; ×: male) in the formula,
or by placing the female parent first. If a non-alphabetical sequence is used, its basis should be clearly indicated.
Article 3
3.1. Hybrids between representatives of two or more taxa may receive a name. For nomenclatural purposes, the hybrid nature of a taxon is indicated by placing the multiplication sign ×
before the name of an intergeneric hybrid or before the epithet in the name of an interspecific hybrid, or by prefixing the term "notho-" (optionally abbreviated "n-") to the term denoting the rank of the taxon (see Art. 3.2 and 4.4). All such taxa are designated nothotaxa.
Ex. 1. (The putative or known parentage is found in Art. H.2 Ex. 1.) ×Agropogon P. Fourn. (1934); ×Agropogon littoralis (Sm.) C. E. Hubb. (1946); Salix×capreola Andersson (1867); Mentha ×smithiana R. A. Graham (1949); Polypodium vulgare nothosubsp. mantoniae (Rothm.) Schidlay (in Futák, Fl. Slov. 2: 225. 1966).3.2. A nothotaxon cannot be designated unless at least one parental taxon is known or can be postulated.
3.3. For purposes of homonymy and synonymy the multiplication sign and the prefix "notho-" are disregarded.
Ex. 2. ×Hordelymus Bachteev & Darevsk. (1950) (= Elymus L. × Hordeum L.) is a later homonym of Hordelymus (Jess.) Harz (1885).
Note 1. Taxa which are believed to be of hybrid origin need not be designated as nothotaxa.
Ex. 3. The true-breeding tetraploid raised from the artificial cross Digitalis grandiflora L. × D. purpurea L. may, if desired, be referred to as D. mertonensisB. H. Buxton & C. D. Darl. (1931); Triticum aestivum L. (1753) is treated as a species although it is not found in nature and its genome has been shown to be composed of those of T. dicoccoides (Körn.) Körn., T. speltoides (Tausch) Gren. ex K. Richt., and T. tauschii (Coss.) Schmalh.; the taxon known asPhlox divaricata subsp. laphamii (A. W. Wood) Wherry (in Morris Arbor. Monogr. 3: 41. 1955) was believed by Levin (in Evolution 21: 92-108. 1967) to be a stabilized product of hybridization between P. divaricata L. subsp. divaricata and P. pilosa subsp. ozarkana Wherry; Rosa canina L. (1753), a polyploid believed to be of ancient hybrid origin, is treated as a species.Recommendation 3A
3A.1. The multiplication sign ×, indicating the hybrid nature of a taxon, should be placed so as to express that it belongs with the name or epithet but is not actually part of it.
The exact amount of space, if any, between the multiplication sign and the initial letter of the name or epithet should depend on what best serves readability.
Note 1. The multiplication sign × in a hybrid formula is always placed between, and separate from, the names of the parents.H.3A.2. If the multiplication sign is not available
it should be approximated by a lower case letter “×” (not italicized).
PS: Dato che il forum è abilitato al riconoscimento del simbolo matematico
×, ho provveduto a sostituire tutte le
× o
× nei titoli delle discussioni.
Saluti,
Luca