222 NORTH AMERICAN FLORA [Volume 25 



Leaves unifoliolate, evergreen. 



Berry usually of an elongate type, commonly mamillate at the apex. 



Rind of the berry 3-7 em. thick ; berry large, 12-20 cm. long, 6-15 cm. 



broad ; pulp but slightly developed, the juice often not abundant nor 



very acid. 1. C. Medica. 



Rind of the berry relatively thin ; berry commonly decidedly smaller ; 



pulp well developed, the juice usually abundant and very acid. 



Berry of medium size, 6-10 cm. long, 3.5-S cm. broad ; pulp light 



colored ; leaflets often pointed ; flowers 3-5 cm. broad. 2. C. Limonum. 



Berry averaging decidedly smaller, 3.5-6.5 cm. long, 2.8-5 cm. broad ; 

 pulp greenish ; leaflets commonly rounded at the apex ; flowers 

 2-2.5 cm. broad. 3. C.Lima. 



Berry globose or subglobose, not mamillate. 

 Twigs and pedicels glabrous. 



Pulp of the berry sweet or sour ; petioles commonly narrowly winged 



or wingless. 4. C. Aurantium. 



Pulp of the berry bitter and sour; petioles often broadly winged. 5. C. vulgaris. 



Twigs and pedicels hispidulous. 6. C. decumana. 



Leaves trifoliolate, deciduous. 7. C. trifoliata. 



1. Citrus Medica L. Sp. PI. 782. 1753. 



Citrus tuberosa Mill. Gard. Diet. ed. 8. 1768. 



A glabrous shrub or small tree, 3 or 4 m. high ; branches unarmed, or armed with rather 

 short, stout, sharp more or less horizontal thorns 1-3.5 cm. long ; petioles usually wingless ; 

 leaves evergreen, unifoliolate ; leaflet oblong to elliptic, occasionally somewhat oblong- 

 obovate, 12-20 cm. long, 4-6 cm. broad, rounded and more or less emarginate at the apex, 

 sometimes acutish, dull green, the margin serrulate-crenate ; flowers axillary in compact 

 clusters of 3-10; petals oblong, white within, tinged with purple on the outside; berry 

 usually very large, oblong to nearly globose, 12-20 cm. long, 6-15 cm. in diameter, often 

 mamillate at the apex, smooth or coarsely wrinkled, deep-orange or bright-yellow ; rind 

 3-7 cm. thick ; pulp often rather dry, acid and somewhat bitterish or sweetish. 



Type locality : Southern Asia. 



Distribution : Widely cultivated ; thoroughly naturalized in tropical and subtropical regions. 



Illustrations : Bentlev & Trimen, Med. PI. 1 : pi. S3; Risso & Poiteau, Hist. Nat. Orangers 

 pi. 96-101 ; Nichols. Diet. Gard. 1 : f. 463 ; Cvcl. Am. Hort. /. 474 ; Britton, N. Am. Trees/. 53S ; 

 Hume, Citrus Fruits pi. If); Tourn. Inst. pi. 395, 396. 



2. Citrus Limonum (L-) Risso, Ann. Mus. Paris 20 : 201. 1813. 



Citrus Medica Limon L. Sp. PI. 782. 1753. 



Limon vulgaris Mill. Gard. Diet. ed. 8. 1768. Not Citrus vulgaris Risso, 1813. 



A small, often spreading shrub, or a tree 3.5-7 m. in height with grayish bark and smooth, 

 angular or roundish, usually thorny branches ; petioles wingless or occasionally winged ; 

 leaflet oblong-elliptic to ovate-oval, 5-11 cm. long, 3-5 cm. broad, crenate, acute or acu- 

 minate at the apex ; flowers usually solitary, or in pairs, axillary ; petals white within , 

 purplish on the outside; berry ellipsoid to oval or ovoid, 6-10 cm. long, 3.5-8 cm. broad, 

 often mamillate at both base and apex, smooth or coarsely wrinkled, light-yellow, the rind 

 thin, the pulp abundant, light-colored, very juicy and acid ; seeds oval, pointed. 



Type locality : Southern Asia. 



Distribution: Widely cultivated ; naturalized in tropical and subtropical regions. 



Illustrations : Berg & Schmidt, Off. Gew. 4 : pi. 31 f; Bentley & Trimen. Med. PI. 1 : pi. 

 54; Britton, N. Am. Trees/. 535,536 ; Risso & Poiteau, Hist. Nat. Orangers pi. 84; Hume, Citrus 

 Fruits pi. 11, f. 30. 



3. Citrus Lima L,unan, Hort. Jam. 451. 1814. 



Limon spinosum Mill. Gard. Diet. ed. 8. 1768. Not Citrus spinosa S. G. Gmel. Reise Russl. 3 : 



278. 1774. 

 Citrus Medica acris Martyn ; Mill. Gard. Diet. ed. 9. 1797. 

 Citrus spinosissima G. Meyer, Fl. Esseq. 247. 1818. 

 Citrus acida Roxb. Fl. Ind. 3 : 390. 1832. 



Citrus Limetta Wight, Ic. 3 :i : 4, in part. 1845. Not C. Lime/la Risso, 1813. 

 Citrus Aurantium spinosissima Griseb. Fl. Brit. W. Ind. 132. 1859. 

 Citrus medica acida Hook. Fl. Brit. Ind. 1 : 515. 1872. 

 Citrus Hystrix acida Bonavia ; Urban, Symb. Ant. 4 : 321. 1905. 



A small, more or less straggling shrub or tree, attaining a maximum height of 5 or 6 

 m., with armed branches, the thorns mostly small, sharp and numerous; petioles winged ; 

 leaflet oblong-elliptic to oval, 6.5-9 cm. long, 1.7-5 cm. broad, commonly rounded at the 



