150 WILSON EXPEDITION TO CHINA 



Western Hupeh: Ichang, hedgerows, alt. 1-300 m., May 1907 

 (No. 2231; tree, 6 m. tall). Shensi: Tai-pei-shan, 1910, W. Purdom. 

 Korea: Quelpaert Island, October 1906, U. Faurie (No. 483); April 

 16, 1908, Taquet (No. 4617); April 1909, Taquet (No. 2715). 



This tree is undoubtedly indigenous in northern China and occurs wild or culti- 

 vated over a large part of the Empire. The fruits are used in medicine, and the 

 tree as a stock upon which to graft forms of Citrus. It is called Kou chii. 



In Japan the Chinese character pronounced Chih (Giles, Chin. Diet. ed. 2, No. 

 1864), in China is applied to this species and pronounced " Karatachi." This 

 character, rarely used alone in Chinese, is usually in combination, as Chih shih 

 (Chih fruit) and Chih K'o (Chih peel), two common drugs. It is, however, by 

 no means certain that these drugs are yielded by Poncirus trijoliata. Further 

 study will be needed to determine the application of these names in China. It 

 is possible that the Chih fruit and Chih peel are produced by two or more differ- 

 ent species of citrous fruits, among them perhaps Poncirus trijoliata.'^ This species 

 was introduced into Japan many centuries ago but is not native there. 



This tree which is commonly called Citrus trijoliata (less often Aegle sepiaria) 

 differs from Citrus in so many and such important characters that it seems prefer- 

 able to consider it as belonging to a distinct genus. The deciduous leaves are tri- 

 foliate, the flower buds form in early summer and being protected by bud scales 

 pass the winter in a dormant condition. The flowers open in early spring, being 

 almost sessile and borne on old wood. The corolla opens nearly flat and the petals 

 are narrowed to a claw at the base; the stamens are entirely free; the ovary is 6-8 

 (usually 7) celled; the fruits are densely and finely pubescent; the pulp vesicles 

 have hairlike appendages with expanded tips bearing enlarged pitted thick-walled 

 cells, which secrete a viscous fluid. The pith has transverse plates of thick-walled 

 cells. The stomata of the green twigs are located at the bottom of deep narrow 

 pits. The seedlings have a number of small, linear spirally arranged cataphylls 

 which gradually merge into normal leaves.^ 



fig. (crude), cited from Japanese ed. Osaka, 1713. — T'u shu tsi ch'eng, 1728 

 (see Bretschneider, 1. c, 71) Sect. 4, Science, Div. 20, Botany (Ts'ao mu), Bk. 302, 

 3 pp. with 1 plate, cited from large reprint. — Wu Ch'i-chtin, Chih wu tning shih 

 t'u k'ao (see Bretschneider, 1. c, 72), Bk. 35, fol. 61, plate, good fig., also supplements, 

 Ch'ang Pien, Bk. 22, fol. 57 (1848). 



^ There is a sterile specimen from which the blades of all the leaves have fallen 

 leaving the rather widely winged petioles attached, that is labeled, apparently in 

 Henry's handwriting: 



" Weucheo (Chi-K'o). Fruit used by Chinese medicinally (only)." 

 This specimen though too defective to determine is certainly not Poncirus tri- 

 foliata but a true Citrus. Wilson's No. 4733, small, thick, rough-skinned fruits in 

 spirits collected at Hokiang Hsien in Szech'uan still have a few leaves attached 

 which show elongate obovate petioles 17 X 8.5 mm., and may possibly belong 

 here. It is impossible to decide without better material. 



2 These differences were noted by Penzig in his Studii botanici sugli Agrumi, 

 but as he erroneously considered the tree to belong to Aegle he did not deem it 

 necessary to justify its separation from Citrus. See also Swingle, The Limitation 

 of the Satsuma Orange to Trifoliate-Orange Stock (in Circular Bur. PI. Indust. 

 U. S. Dept. Agric. XLVI. 10, fig. 1-6, t. 1 [1909]), and Variation in First Genera- 

 tion Hybrids, etc., in Comptes rendus et rapports. 4 conference international de 

 G6netique d Paris, 1911, p. 382 (1913). 



