Naturalisation in Extra-Tropical Countries. 269 



Bay (Fred. Turner). It produces the Ceara-Rubber. Its cultiva- 

 tion is not difficult, and its growth remarkably rapid. It could 

 only be grown in regions free of frost. Mr. Holtze, at Port 

 Darwin, had the first grand success with this plant in Australia, 

 seeds from Kew-Grardens having been placed by the author at his 

 disposal ; his plants attained a height of 12 feet in little more than 

 a year. Perhaps the plant must be regarded as strictly tropical r 

 and as then not admissable within the scope of this work. Still 

 near Port Curtis, at the verge of the tropics, it grows fast arid 

 matures seeds ; the trees there already are over 20 feet high 

 [Edgar]. In Ceylon it thrives well up to 3,000 feet elevation, 

 content with poor dry soil [Dr. Trimen]. Easily reared from 

 seeds or propagated from cuttings ; the germinating is expedited 

 by filing the shell of the seeds and placing them in coir ; when 

 sprouting they should be put into the soil with the germ downward. 

 In Ceylon the plant has grown as much as 20-30 feet in two years ; 

 the plants should be placed about 10 feet apart. It is best to wait 

 with tapping till the trees are five years old [Keir Leitch]. 



ZKanihot utllissima, PohL* 



The Bitter Cassava or Tapioca- Plant. Eastern Brazil. Closely 

 allied to M. Aipi, producing varieties with roots of poisonous 

 acridity and with roots perfectly harmless. The tubers attain a 

 length of 3 feet and a weight of 30 Ibs. Exceptionally 100 Ibs. of 

 Cassava-roots are obtained from a single stock. They can be 

 converted into bread or cakes, the volatile poison of the milky sap 

 being removed through pressing the grated root in first instance, 

 the remaining acridity being expelled by heat. The starch, heated 

 in a moist state, furnishes tapioca. Manihot is abundantly culti- 

 vated in many places, thus at Caraccas, where the singularly 

 uniform temperature throughout the year is only 60 to 70 F. In 

 Jamaica cultivated up to 4,000 feet [W. Fawcett]. Thrives well* 

 even in the vicissitudinous clime of Central Australia. Both sorts 

 of Cassava are also quite suited for the sub-tropic country towards 

 Port Curtis, where the severest drought has very little effect on 

 them, good tapioca being made already in the district [Edgar]. 

 Exceeds in productiveness even the Sweet Potato. The roots can 

 be left in the ground till required, and they thus continue to grow. 

 One-fourth of their substance is starch, which is one of the best for 

 cookery. It is a very exhausting crop, and thus stands in need of 

 rich soil and copious manuring. The propagation is effected by 

 cuttings from the ligneous part of the stem. The soil, destined for 

 Cassava, must not be wet. In warm countries the tubers are 

 available in about eight months, though they still continue to grow 

 afterwards. The growth of the plant upward is checked by break- 

 ing off the tops. The Bitter Cassava is the more productive of the 

 two. The yellowish tubers do not become soft by boiling, like 

 Aipi. 



