49.1. When a genus or a taxon of lower rank is altered in rank but retains its name or the final epithet in its name, the author of the earlier, name- or epithet-bringing legitimate name (the author of the basionym) must be cited in parentheses, followed by the name of the author who effected the alteration (the author of the new name). The same holds when a taxon of lower rank than genus is transferred to another genus or species, with or without alteration of rank.
Ex. 1. Medicago polymorpha var. orbicularis L. (1753) when raised to the rank of species becomes M. orbicularis (L.) Bartal. (1776).
Ex. 2. Anthyllis sect. Aspalathoides DC. (1825) raised to generic rank, retaining the epithet Aspalathoides as its name, is cited as Aspalathoides (DC.) K. Koch (1853).
Ex. 3. Cineraria sect. Eriopappus Dumort. (Fl. Belg.: 65. 1827) when transferred to Tephroseris (Rchb.) Rchb. is cited as T. sect. Eriopappus (Dumort.) Holub (in Folia Geobot. Phytotax. 8: 173. 1973).
Ex. 4. Cistus aegyptiacus L. (1753) when transferred to Helianthemum Mill. is cited as H. aegyptiacum (L.) Mill. (1768).
Ex. 5. Fumaria bulbosa var. solida L. (1753) was elevated to specific rank as F. solida (L.) Mill. (1771). The name of this species when transferred to Corydalis DC. is to be cited as C. solida (L.) Clairv. (1811), not C. solida (Mill.) Clairv.
Ex. 6. However, Pulsatilla montana var. serbica W. Zimm. (in Feddes Repert. Spec. Nov. Regni Veg. 61: 95. 1958), originally placed under P. montana subsp. australis (Heuff.) Zämelis, retains the same author citation when placed under P. montana subsp. dacica Rummelsp. (see Art. 24.1) and is not cited as var. serbica "(W. Zimm.) Rummelsp." (in Feddes Repert. 71: 29. 1965).
Ex. 7. Salix subsect. Myrtilloides C. K. Schneid. (Ill. Handb. Laubholzk. 1: 63. 1904), originally placed under S. sect. Argenteae W. D. J. Koch, retains the same author citation when placed under S. sect. Glaucae Pax and is not cited as S. subsect. Myrtilloides "(C. K. Schneid.) Dorn" (in Canad. J. Bot. 54: 2777. 1976).
Note 1. Art. 46.5 provides
for the use of parenthetical author citations preceding the word
"ex", after some names in groups with a starting point
later than 1753.