158 NEW SPECIES OF IVIANIHOT 



Manihot piauhyensis, Ule. — M. piauhyensis is of similar 

 habit to M. heptaphylla, but is rather smaller, bemg only 

 from 6 to 16 ft. in height. The leaves are bright green, 

 broadly obovate or oblong-obovate, and are divided into 

 five segments. The fruits are distinguished from those of 

 31. heptaphylla by being winged at the corners, but the 

 seeds are very similar to those of the latter species. 



M. piauhyensis is widely distributed in the south- 

 eastern portion of the State of Piauhy along the Bahia 

 boundary, where it occiu-s on the lower sandstone moun- 

 tain ranges. 



Collection of the Rubber. — In Brazil the rubber of M. 

 dichotoma is obtained by making incisions in the bark of 

 the stem and collecting the latex in cups ; the latex very 

 quickly coagulates spontaneously. M. heptaphylla and 

 M. 2)ici>uhyensis are usually tapped at the base of the stem 

 only, by the method employed for M. Glaziovii ; the 

 latex is allowed to run into a hole made in the ground and 

 to remain there until coagulation has occm-red. It is 

 stated that the amount of rubber collected annually in 

 Brazil from the three species during recent years is ap- 

 proximately as follows : 400 to 500 metric tons from 

 M. dichotoma, 500 tons from M. heptaphylla, and at least 

 600 tons from M. piauhyensis. If these figures can be 

 accepted as correct, it would appear that haK or more 

 of the total Mani9oba rubber exported from Brazil is 

 derived from the three new species. 



Value for Cultivation. — It is stated that the yield of 

 rubber obtained from M. dichotoma, M. heptajjhylla, and 

 31. piauhyensis is usually greater than that fm-nished 

 by 31. Glaziovii, and Ule expressed the opinion that 

 wherever the conditions are suitable, the ncAV species 

 should be cultivated in preference to the Ccara tree. 31. 

 dichotoma is regarded as most suitable for good, loamy 

 soils, and the other two species for light, sandy soils. 



Plantations of the trees have been formed in Brazil, 

 the seeds being usually planted " at stake " about 2 

 metres apart, giving approximately 1,000 trees per acre. 

 No definite figures as to the actual results obtained by 

 tapping the cultivated trees on a large scale arc, however, 

 available. According to published statements 31. dicho- 

 toma will yield from 100 to 200 grams of rubber per tree 

 annually, whilst the amount obtainable from the other 



