RUTACEAE. — PONCIRUS 149 



narrowly winged in the sweet and broadly winged in the sour orange; the leaves 

 and flowers of the two species have a very distinct odor. The two species show 

 decided differences in their soil requirements and in their susceptibility to the at- 

 tacks of fungous diseases. Many other minute but constant divergences are shown 

 between these two oranges in all their organs. These two plants, then, super- 

 ficially so similar are in reality very unlike and should by no means be united as 

 varieties of one species. 



The earliest available name for the sweet orange as a species distinct from the 

 sour orange is Citrus sinensis Osbeck. Osbeck in the German edition of his Voyage 

 applies the name to both the mandarin orange and the tight-skinned or common 

 orange, but expressly excludes the sour orange. He had previously in the Swedish 

 edition of his work called the sweet orange seen in Spain Citrus sinensis and the sour 

 orange Citrus Aurantiitm, but in an incidental way, probably not establishing the 

 name though referring to it clearly enough to make it plain that of the two forms 

 included in Citrus sinensis in 1765 the type must be held to be the common orange 

 grown in Spain and China both, and not the mandarin orange. There is no war- 

 rant for using Citrus Aurantiutn Linnsieus for the sweet orange, as Loureiro, Risso, 

 Hooker and many other authors have done. 



All of the commonly cultivated species of Citrus, with the exception of the lime 

 (Citrus aurantifolia (Christman) Swingle, see Jour. Washington Acad. Sci. III. 

 463-465 [1913]), seem to be native in China and many are found nowhere else. 

 In addition to the species listed above, there are a number of puzzling forms col- 

 lected by Wilson and others which do not seem to fit into any of the species of 

 Citrus known as yet. Some of the specimens may represent hybrids but until 

 more complete material is at hand it will be impossible to place them with any 

 degree of certainty. 



PONCIRUS Raf. 

 Determined by Walter T. Swingle. 



Poncirus trifoliata Rafinesque, Sylva Tell. 143 (1838).^ 



Citrus trifoliata liinnaena, Spec. ed. 2, 1101 (1763). — • Hooker f. in Bat. Mag. 



CVI. t. 6513 (1880). — Engler in Engler & Prantl, Nat. Pflanzenfam. III. 



Abt. IV. 196, fig. 114 (1896). 

 Citrus trifolia Thunberg, Fl. Jap. 294 (1784). 

 Aegle (?) sepiaria De CandoUe, Prodr. I. 538 (1824). — Penzig in Ann. di 



Agricoltura (2), No. 116, p. 132-149, t. 11, 13, 14 (Studii Bot. Agrumi) 



(1887). — Nicholson in Card. Chron. ser. 3, XXVII. 269 (1900); in Flora & 



Sylva, III. 65 (1905). 

 Pseudaegle sepiaria Miquel in Ann. Mus. Lugd.-Bat. II. 83 (1845). 

 Citrus triptera Carrifere in Rev. Hort. 1869, 15, fig. 2 (non Desfontaines). — Du 



Breuil in Risso & Poiteau, Hist. Nat. Orang. ed. 2, 145, t. 195 bis (1872). 

 Limonia trichocarpa Hance in Jour. Bot. XV. 258 (1882) .^ 



^ The following Prelinnean name belongs here : 



Ssi, vulgo Karatats hanna, aliis Gees, Kaempfer, Amoen. 801, t. (1712). 



2 Vernacular name: " Kou chii " (Giles, Chin. Diet. ed. 2, No. 6140), Li Shih- 

 chen, Pen ts'ao kang mu, 1596 (see Bretschneidcr, Bot. Sin. I. 54), Bk. 36, fol. 

 5-7, figure in Atlas under leafy trees (Kuan mu), very crude, cited from 1655 ed. 

 — Wang Ch'i, San ts'ao Vu hui, 1607 (see Bretschneidcr, 1, c, 183), Bk. 84, fol. 4, 



