REPORT OP THE SUPERINTENDENT OF GARDENS. 65 



Mesquit tree of Texas, AJgarohia glandulosa, wbich yields a non-elastic 

 gum of the nature and jDossessing all the essential qualities of gum. 

 arable. 



cmcnoNAs. 



During the past ten years a continuous supply of young plants of sev- 

 eral species of cinchona has been maintained by a yearly propagation 

 of young plants equal to the numbers distributed. Plants have been 

 sent to California, and to several of the Southern States, mainly to 

 Florida. The reports that have reached the Department do not indi- 

 cate success in their culture, owing to adverse climatic influences. Ex- 

 periments here show that none of the species will stand the slightest 

 frost without injury, and even in the equable atmosphere of the green- 

 house their vitality is impaired when the temperature is below 50°. 

 Whether or not the climatic conditions for the growth of cinchonas ex- 

 ist in any portion of the country is a question not yet solved, but, so far 

 as our i^resent knowledge warrants an opinion, further experiments 

 should be confined to the locality of San Diego, Oal., as offering greater 

 promise of success than any other point. 



In the recently-formed cinchona-plantations in India the best results 

 are said to be obtained in a warm, equable, and very moist atmosi)here, 

 at elevations where the mean yearly temperature indicates 64°; and in 

 those established in St. Helena, the plants flourish well at an elevation 

 of 1,500 feet above sea-level, in rich lands, bathed in moistui-e, the mean 

 temperature for the year being 60"^. 



Dr. J. E. Howard, of England, (high authority in everything relating 

 to the cinchona,) in the transactions of the Linnean Society, remarks 

 that " it must be remembered that these are mountain-plants, loving 

 free air and alternate mist and sunshine, while the hot, close atmosphere 

 of the lower valleys is always injurious to their perfection as quinine- 

 producing iilants." It is shown in the reports of the Signal-Oflice that 

 the mean temperature for the year at San Diego is 60°, the highest 

 monthly mean reaching CS'^ in August, and the lowest monthly mean 

 being that of 53<^ in January and February. So far as thermometric 

 figures indicate atmospheric temperature, the climate of San Diego cor- 

 responds with that of St. Helena, but it is well known that the ther- 

 mometer alone is not a safe guide in comparisons of this kind ; the hy- 

 grometrical condition of the atmosphere being of equal, if not of greater, 

 importance as regards vegetable growth. Experience in the culture of 

 several species here confirms the reports that CincJiona succiruhra is the 

 most robust in growth. This species predominates in artificial planta- 

 tions on account of its rapid growth. 



EUCALYPTUS GLOEULUS. 



The interest attached to the Australian blue-gum tree, both in rela- 

 tion to its gTcat rapidity of growth and its reputed hygienic qualities, is 

 increasing, and the demand for plants and definite information regarding 

 their culture and sanitary value continues unabated. There is no special 

 difficulty in propagating the plant. The seeds are small, very similar in 

 size and appearance to those of the onion, and vegetate rapidly when sown 

 in good condition. The young plants are rather delicate at first, but after 

 a few weeks they grow with great rapidity. In the greenhouse they have 

 reached a height of 4 feet in as many months from the seed, and young 

 plants 1 foot in height planted out in May grow from 4 to G feet before 

 5a 



