1921] REHDER, NEW SPECIES, VARIETIES AND COMBINATIONS 81 



greater number of stamens with fertile anthers and usually normal ovar- 

 ies; they therefore occasionally produce fruits. The form with perfectly 

 double flowers without stamens and a rudimentary ovary changed into 

 two leafy carpels was first described by Loiseleur (in Nouv. Dull. v. 20 

 1912) as "C6risier i fleur double" and is apparently the form now called 

 P. Cerasus f. Rhexii Voss. 1 



The double-flowered form of P. avium L. seems to have been unknown 

 to Linnaeus, but the Prunus-Cerasus sylvestris plena mentioned by Wes- 

 ton in 1770 can hardly be any other than this form which according to 

 Loiseleur (in Nouv. Duhamel, v. 11) is the Cerasus major ac sylvestris 

 multipliciflore of Tournefort (Inst. 627) and the Cerasus major sylvestris 



fl 



It apparently originated in 



France some time before 1700, but seems to have been little known out- 

 side of France before the beginning of the 19th century. Its correct name, 

 therefore, is P. avium f. plena Schneider (111. Handb. Laubholzk. i. 616 

 [1906J). 



Prunus mahaleb f. xanthocarpa, comb. nov. — Cerasus Mahaleb 2. 

 fructo flavo Hort. apud Loudon, Arb. Brit. n. 707 (1838). — Cerasus 

 Mahaleb a. xanthocarpa Roemer, Syn. Monog. m. 80 (1847). 2 — Prunus 



? Cerasus Maha- 

 uen. — ? Prunus 



) (1892). — Pru- 



Mahaleb var. fructu luteo 



leb var. fructu albo Lava 



mahaleb var. fructo albo 



nus Mahaleb var. chrysocarpa Nicholson in Kew Handlist Arb. I. 143 



(1894), nomen. — Gard. lxii. 181, fig. (1902), nomen. — Schneider, 



Handb. Laubh. i. 617 (1907), as forma. 



This form with yellow fruit I find first mentioned in 1812 by Loiseleur 

 (in Nouv. Duhamel v. 7) and it must have been well known at that time, 

 as he says that the variety with yellow fruit is more widely distributed 

 in gardens than the variety with large leaves. The form enumerated as 

 "fructu albo" by La valine and by Mouillefert is unknown to me, but 

 probably it does not differ much from the form with yellow fruit. 



1 P. Cerasus f. Rhexii Voss, Vilmorin's Blumengart. I. 233 (1894).— Bailey, Cycl. 

 Am. Hort. in. 1454 (1901), as var. — ? Cerasus acida y. plena Roemer, Syn. Monog. in, 

 65 (1847).— Cerasus acida 5. Rhexii Kirchner in Petzokl & Kirchner, Arb. Muse. 252 

 (1804). — Cerasus avium fi. pi. serotino Booth's Cat. ex Kirchner, 1. c. (1804), as synon. — 

 Cerasus Rhexii Hort. ex Kirchner, 1. c. (1864), as synon. — Prunus Crrasus var. 

 Rhenii[sic] Jaeger, Ziergeh. 394 (1865).— Cerasus caproniana ranunculifiora Vanhoutte, 

 Fl. des Serres xvn. t. 1805 (1808).— Cerasus vulgaris Rhexii Hartwig & Ruempler, 

 Baum. & Straueh. 145 (1875).— Prunus Cerasus Rhexii plena, Jaeger & Beissner, 

 Ziergeh. ed. 2, 266 (1884). — P. Cerasus caproniana ranunculifera } Jaeger & Beissner, 

 I. c. (1884).— P. Cerasus Rhexii Jlore pleno Wittmack in Deutsch. Garten-Zeit. 224, 

 fig. (1886).— D. in Garden lxxviii. 227 fig. (1914).— Wayland in Gard. lxxxi. 184, 

 (1917).— E. W. S. in Garden lxxxiii. 94, fig. (1919). P. Cerasus jlore albo pleno Rhexl. 

 Hartwig, 111. Geholzb. 287 (1892).— P. Cerasus f. ranunculifiora Vox*, Vilmorin's Blum- 

 engart. 1. 33 (0894). — Prunus caproniana serotina flore pleno Zabel in Biessner, Schelle 

 & Zabel, Handb. Laubholz-Ben. 240 (1903).— P. Cerasus subsp. vulgaris f. plena Loisl. 

 apud Voss in Putlitz & Meyer, Landlex. VI. 347 (1914), excl. synom. 



2 Roemer quotes a synonym "var. hortensis Spach" but Spach (Hist. Veget. I. 409, 

 1834) does not give a varietal name to thisform,heonly mentions it in the description 

 " Drupe noir (jaune dans une vuriete de jardin). ,; 



