This section is from the book "Rubber And Rubber Planting", by R. H. Lock. Also available from Amazon: Rubber And Rubber Planting.
In 1907 extensive reports were published in Germany emphasising the importance of Manitoba rubber as distinguished from ordinary Ceara. This rubber was said to be derived mainly from three species of Manihot M. dichotoma, M. heptaphylla and M. piauhyensis. Formerly it appears to have been confused with the produce of Hancorhia speciosa. The seed of the above-named species of Manihot has been widely advertised for planting in tropical countries, but the small amount of evidence at present available seems to show that they are all less satisfactory than M. Glaziovii for plantation purposes. Very large yields have been attributed to young trees of the Manitoba species in Brazil. The tapping of M. dichotoma is usually carried out with the knife. When the latex is collected in vessels it begins at once to coagulate. It is then moulded with the hands into balls, which are usually pressed between rollers and afterwards thoroughly dried. Manihot piauhyensis and M. heptaphylla, on the other hand, are tapped at the base of the stem, and the latex allowed to flow upon the ground.
 
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