IN EXTRA-TROPICAL COUNTRIES. 165 



height of 6 feet. Pods straight, cylindrical, many-seeded. Exten- 

 sively cultivated in warm zones for indigo, and probably hardy in 

 warmer temperate regions. The plant is frequently sold fresh by 

 the grower to the factories. The Indigo plant requires a rich 

 friable soil, neither too moist nor too dry. The seeds are sown in 

 furrows about a foot apart, and in hot damp climes the plant can 

 be cut in about two months, as soon as it begins to flower ; in six 

 or eight weeks it yields a second crop, and under favourable cir- 

 cumstances as many as four crops can be gathered in a year. The 

 plants have to be renewed every year, as the old ones do not yield 

 such an abundant produce. Bright sunshine favours the develop- 

 ment of the dye principle, but frequent rains cause a more luxuriant 

 growth (Hartwig). 



Inula Helenium, Linne. 



The Elecampane. Middle and South Europe, Middle Asia east- 

 ward to Japan. A perennial herb. The bitter and somewhat 

 aromatic root, for the sake of its stimulating and tonic properties, 

 is used in medicine. It contains also the amylaceous inulin and 

 the crystalline helenin. With the Mullein (Yerbascum Thapsus), 

 L., adaptable for scenic effects. 



Ipomcea Batatas, iPoiret.* (Batatas edulis, Choisy.) 



The Sweet Potato. Tropical South America. First brought to 

 Europe from Brazil. It proved well adapted also for the southern 

 part of Australia and for New Zealand. The tubers afford a palat- 

 able food, more nutritious than ordinaiy potatoes. Can be well 

 utilized for starch. Varieties with red, white and yellow roots 

 occur. Each tuber weighs generally from 3 Ibs. to 5 Ibs., but may 

 occasionally attain to 56 Ibs. The yield is from 200 to 300 bushels 

 from an acre. 



Ipomcea Batatilla, G. Don. 



Cooler regions of Venezuela! The tubers serve as sweet potatoes. 

 Similarly useful, I. platanifolia, Roem. et Schult., from Central 

 America, and I. mammosa, Choisy, from Amboina. 



Ipomoea Calobra, Hill and Mueller. 



Central Australia. The large roots a fair esculent. 



Ipomoea magapotamica, Choisy. 



South Brazil and Argentina. The root attains several pounds 

 weight, and serves as jalap. Propagation by pieces of the root or 

 from cuttings of the underground stem. 



