328 FOREST CULTURE AND 
Manihot Aipi, Pohl.—The Sweet Cassava. Tropi- 
cal South America, but traced as far south as the 
Parana River. The root is reddish and harmless; it 
can therefore be used, unlike those of the following 
species, without any further preparations than boiling, 
as a culinary esculent, irrespective of its starch being 
also available for tapioca. Both are somewhat woody 
plants, several feet high, and they are too important 
to be left altogether unnoticed on this occasion, al- 
though we have no evidence that they will prove 
productive even in those parts of Victoria which are 
free of frost. The Aipi has ligneous, tough fibres, 
stretching along the axis of the tubers, while gener- 
ally the roots of the following species are free of this 
central woody substance. 
Manihot utilissima, Pohl.—The Bitter Cassava or 
Tapioca- plant. Tropical South America. Closely 
allied to the former, producing varieties with roots of 
poisonous acridity, and with tubers perfectly harm- 
léss. The tubers attain a length of 3 feet; they can 
be converted into bread or cakes, the volatile poison 
of the milky sap being destroyed through pressing 
of the grated root in first instance, and the remain- 
ing acridity is expelled by the heating process. The 
starch, heated in a moist state, furnishes the tapioca, 
Manihot is abundantly cultivated at Caracas, where 
the singularly uniform temperature, throughout the 
year, is only 60 degrees to 70 degrees F. It is a very 
exhausting crop, and stands thus in need of rich soil 
and manuring. The propagation is effected by cut- 
tings from the ligneous part of the stem. ‘The soil 
destined for Cassava must not be wet. In warm coun- 
tries the tubers are available in about eight months, 
