658 FIELD AND GARDEN PRODUCTS 



tions remain constant there is then no reason why another crop 

 should not follow immediately. 



Virgin Spawn. Whether the spawn is made as bricks or as 

 flake material, the point of greatest importance is to secure a so- 

 called virgin spawn, or a new growth of the mycelium of Agaricus 

 campestris, which has never exhausted itself to any degree by the 

 production of mushrooms. The problem of securing such virgin 

 spawn is a difficult one, and as usually met in England and France 

 it leaves to chance the quality and other characters of the mush- 

 rooms which may grow from such spawn. If, accidentally, mush- 

 rooms are found growing on the lawns or in pastures, or if myce- 

 lium is located in such situations, small trenches are dug beneath 

 the sod and these are filled with rich manure, with the hope that 

 the vigorous-growing mycelium will penetrate this manure in the 

 course of a few weeks. This usually occurs, and the spawn is said 

 to be very good when one prevents the production of mushrooms 

 by this spawn, and, if possible, by any of the mycelium in the 

 vicinity. When the manure in the trenches is well penetrated 

 by the mycelium, the spawn is removed and dried, and it is usually 

 termed virgin spawn. It may then be used in the inoculation of 

 spawn bricks or it may be used in the inoculation of small beds, either 

 of which, when penetrated by the growing, mycelium, may in turn 

 be used as commercial spawn, brick or flake, respectively, which is 

 then sold or used in a commercial way. (F. B. 204.) 



(Additional References. B. P. I. B. 85; Cornell E. S. B. 138, 

 168, 227; N. C. E. S. B. 132; Colo. E. S. Cir. 6; Idaho E. S. B. 

 27; Ind. E. S. B. 98; U. S. Div. of Bot. Cir. 13; Mich. E. S. B. 

 208 ;N. H. E. S. B. 59.) 



THE CASTOR BEAN. 



The Castor bean is of the botanical order Euphorbiaceae which 

 also includes many well known cultivated plants, such as the potato, 

 tomato and tobacco. There are many cultural varieties, some of 

 which have been described as separate species, but all intergrade, so 

 that lines of separation between forms can scarcely be distinguished. 

 It is generally considered that all of the different forms or varieties, 

 both wild and cultivated, are derivatives from the single species 

 Ricinus communis. 



Varieties. There are two primary races of the castor bean ; 

 one a perennial bushy plant with large seeds, and one with small 

 seeds. The former yields in considerable quantity an inferior oil 

 employed only for illumination and lubrication, or in the various 

 manufactures. The small seeded variety yields a superior oil, the 

 qualities of which constitute it the medicinal oil of commerce. 



This plant grows through a very wide range of climates, from 

 the tropics to the north temperature zone, and varies in its size and 

 habit of growth, from a perennial tree thirty or more feet in height, 

 to an annual maturing seed in a very short season and growing only 

 three or four feet in height. (Hawaii E. S. B. 2.) 



Cultivation and Harvesting. The castor bean thrives in the 

 sandiest soil, and its culture is very simple. The seeds germinate 



