388 



THE AORICUTURAL NEWS. 



December 6, 1913. 



FRUIT AND FRUIT TREES. 



NEW OITRUS TREES FROM CHINA. 



One of the most remarkable of the wild species of the 

 genus Citrus is definitely described for the first time in the 

 Journal nf Aqricidtural Research, Vol. I, No. 1. 



The reader may remember that the question of wild 

 citrus species was dealt with in the last issue of the Agricul- 

 tural A^ews, and the present account forms therefore, an 

 interesting and important continuation of the sul>iect. 



The species under consideration has been named Citrus 

 Icham/emis, Swingle. As far as is known, this plant is native 

 farther north than any other evergreen species of citrus, only 

 the deciduous C. triroliata having a more northerly range. 

 Be.sides having the most northerly range of any known 

 evergreen species of citrus, it occurs at the highest altitudes 

 reported for any other wild species of the genus. 



C. Ichangends is cultivated in China in the vicinity of 

 Ichang; and it bears a very large lemon-like fruit that is of 

 sufficiently good quality to cause it to be shipped to markets 

 several hundred miles distant. 



In the space of this article it would not be possible to 

 reproduce in full Swingle's description of the species, but it 

 may be noted that the species differs from its congeners in 

 having very large thick seeds and slender leaves four to six 

 times longer than broad, with very large winged petioles of ten 

 as large or larger than the blade. It differs from Citrus 

 Mstri.c, DC, in having oblong rather than triangular wingtd 

 petioles and much larger flowers with conate stamens. The 

 bulky seeds of Citrus Ic/wngensis with their large brown caps 

 and thickly formed cotyledons are not at all unlike those of 

 the African species of hard-shelled citrus fruits belonging to 

 the genera Balsamo-citrus and Aeglopsis. 



A wild species of citrus collected by Hooker and 

 Thompson in 1850 amongst the Khasi hills in As.sam has 

 been described by Swingle as a subspecies, namely, Citrus 

 Jclia'i'tensis latijMs, Swingle. It differs from C. Ic/i-iiiffensis in 

 having the leaves more variable in size and shape with the tips 

 acute, not caudate, the flowers in few-flowered (three to five) 

 panicles instead of solitary, and the fruits oblate instead of 

 prolate spheroidal in .shape. The fact that Hooker and 

 Thompson called this plant a wild or-mge is additional 

 evidence that the lemon-like appearance of the Chinese form 

 is a constant sub-specific character. 



a ropre.sentative of the natural order .Moraceae, and recently 

 introduced to the United States from China. Its fruit, 

 although small, is sweet and edible, and because of its 

 hardiness, the shrub can probably be grown in the southern 

 half of the I'nited States. In (^liina, the leaves are used 

 for feeding silk worms at times when mulberry leaves are 

 scarce. It is believed that it might be usefully employed 

 for hedge purposes, and there appears to be little doubt that 

 the fruit if successfully crossed with the Osage orange will 

 provide a progeny yielding produce of great value as food 

 for live stock. 



POSSIBLE USES OF THE SPECIES. 



The large size of the "seeds makes it probable that 

 Citrtts Ichangensis will produce very vigorous seedlings, and 

 hence it is likely to be of value as a stock on which to graft 

 other citrus fruits. The numerous large seeds, however, 

 possess the drawback of greatly reducing the proportion of 

 juice because of the space they take up. Since the plant is 

 a native of China and Assam and very hardy, its .Miitability 

 for growth in the Southern States is practically a foregone 

 conclusion, and there is every probability that this species 

 will play a great part in the development of citrus cultiva- 

 tion in America. In conclusion it may be pointed out that 

 the discovery of C. Iclidugcusis in a part of China as accessi- 

 ble as Ichang is a further proof of the rich harvest of new 

 species of plants that awaits the botanist and agriculturist 

 in China. 



In connexion with the above account, attention may be 

 called to an article in the American Breeders' Magmine 

 (July-September 1913) dealing with Cndrinia tricuspidata, 



DIFFERliNT LIGHT INTENSITrES AND 



PLANT ASSIMILATION. 



Although the subjects used in these experiments did not 

 comprise tropical fruit trees, the importance of the results 

 seems to be sutliciently general to justify their consideration 

 on this page. The significance of the results in relation to 

 tropical seedlings raised under shade and in regard to shade- 

 grown cacao should be noted. 



The subjet-ts of the research were Teucrium scoi-odonia 

 and PisiiM S'tfinim, chosen as being typical shade and sun- 

 loving plants respectively. The various light intensities were 

 obtained by using shelters covered with woven material of 

 different textures. Amongst the conclusions drawn were 

 the following: (1) that a leaf developed in shade can 

 exhibit a higher stimulating energy in direct sunlight 

 than a leaf developed in sunlight (this is attributed 

 to increased chlorophyll content); (2) plants developed 

 in full light are at great disadvantage when transferred 

 to shade compared with those developed in the shade 

 (this emphasizes the modifications which the shaded plants 

 undergo); (3) plants developed in low light-intensity increase 

 their energy when transferred to sunlight; (4) when the light- 

 intensity is reduced to one-ninth, the assimilating energy is 

 very low, and the adaptation has been carried to such a point 

 that the leaf is unable to profit by increased illuminations 

 when placed in direct sunlight; (-5) an analogous effect is 

 obtained when young plants are transferred to increased 

 light-intensity, and it is probably due partly to lack of pro- 

 tective tissues and partly to deeper causes depending upon 

 the activity of the protoplasm itself. 



In general, plants seem to have the power of modi- 

 fying their structure and chlorophyll content within their 

 individual limits of adaptability, so that under natural con- 

 ditions, their assimilating power tends to remain constant 

 through the different light intensities. 



Grafted Papaw as an Annual Fruit Tree.— 



According tn the Montldi/ Jlulletin of Ayricullnral Intdligence 

 and Plant /)iseoses (July 1913), the cultivation of this fruit 

 in Florida has been impeded by the fact that its propagation 

 from seed gives very uncertain results, while its propagation 

 from cuttings is too slow to prove remunerative. A 

 successful attempt has been made in grafting desirable stock 

 on young seedlings, so that a yield of f8 to 72 lb. per tree 

 may be obtained in fifteen months. There are indications 

 that the demand for papaws is growing, and that the smaller 

 fruits can be shipped to different markets with success 



To encourage coco nut cultivation an enactment has 

 been parsed in Kedah to allow of the remission of land tax 

 under certain circumstances. (See Agricultural Bulletin, 

 F.M.S., October 1913.) 



