242 



been able to demonstrate this as an actual fact as in the case of the 

 orange, but I feel sure some one may meet with an abnormal specimen 

 which will prove the point. 



The varying intensity of rhythmic waves of growth may come to be 

 regarded as a leading factor in the development of form. These waves 

 certairjiy have todowith the varying sexual characters of trees, as I have 

 shown in other papers. The fact brings us near to a certain knowledge 

 of the origin of form, though we have still to learn what causes the 

 variations in the intensity of these waves. Even in these different 

 forms of citrus fruits the varying forces affect fertility. In the case of 

 the Tangierine orange, in which the secondaiy rhythm has been 

 accelerated to such an extent as to cause aoortion in the whole of the 

 lower carpellary system, the seeds necessarily are not formed. In the 

 case of the Navel, where the secondary wave has only drawn part of 

 the force from the lower, it usually results in so much weakening of the 

 lattei 's power that few or no seeds result. The Navel is usually a seed- 

 less fruit. (Prcceedings of the Academy of Natural Sciences of 

 Philadelphia.) 



ceara rubber. 



This Rubber was noticed in the Bulletin for March, 1895, and the re- 

 sults were given that were obtained in the Public Gardens. 



The following lettter calls attention again to the subject. 



Messrs. Cross and Howard differ very much in their remarks on the 

 elevation at which it grows. According to Mr. Cross, it would appear 

 as if the elevation was not above 200 feet, whereas Mr. Howard has 

 seen it at 3,600 feet. It would grow at greater elevations still in 

 Jamaica, and it may be well to try it all over the island. Applications 

 for a few plants to experiment with, should be addressed to the Direc- 

 tor of Public Gardens, Kingston P. O. 



The price of rubber has risen since Messrs. Silver quoted 2s. 3d. per 

 lb., as the value of some obtained from a tree in Hope Gardens, and 

 Mr. Howard states that the price now is 3s. 3d. per lb. 



Mr. Esme Howard to His Excellency Sir H. A. Blake. 



Barbados, 2nd October, 1897. 



I have been travelling in Mexico and Brazil for some months to exa- 

 mine the habits of the different rubber-producing plants of those coun- 

 tries with a view to finding out which are the most suitable for planta- 

 tions. In Ceara. Brazil, I bought several thousand seeds of the Mani- 

 hot Glaziovii, which I think will grow well in many parts of the West 

 Indies, meaning to distribute them in various islands for the pur- 

 poses of experiment. It seems to me that parts of Jamaica would be 

 well suited for the cultivation of this tree, which produces a good rubber 

 fetching at present where well collected and cured the second highest 

 price of any rubber on the market, viz. about 3/^d. per lb. 



The Manihot Glaziovii will grow well on hill sides in a rocky and 

 rather poor soil. We found it growing in Ceara up to a height of 

 3,600 feet above the sea It is a rapid grower and can be tapped in 

 five years after planting, provided it has grown well. I believe a 

 rainfall of about 100 inches or more is most suitable for it, but it will 

 <do with much less say 65 or 70 inches. 



