327 



as decorative plants in gardens and public places. There a bed of old 

 flowers and slowly yellowing leaves is very unsightly. Consequently the 

 bulbs are lifted and let ripen in another place. The resulting great injury 

 to the root prematurely checks the vegetative growth of the bulbs. The 

 leaves dry before they have lived out their life and their bases, i. e. the 

 scales of the bulbs, remain immature and rich in sugar, thereby forming the 

 desired centre for convenient infection by the fungus. 



In the large field-grown commercial bulbs, the supply of fertilizer 

 enters into the question, since it is desirable to produce very strong bulbs 

 in the shortest possible time. The fertilizer so lengthens the time of growth 

 that many varieties have not finished growth at the fixed time of harvest. 

 The leaves, still green, then possess in every case unique scales and during 

 the storage of the harvested bulbs on the "bulb floors," up to the time of the 

 autumn sales, Penicillium has ample time fo attack the scales, which remain 

 rich in sugar, and to destroy them. It is a matter of course that varieties 

 ripening especially late will exhibit this bad condition and the growers, 

 therefore, speak of "ring diseased races." 



The testing of the bulbs is accomplished by cutting superficially through 

 the tip of the neck during the dormant period. If the cross-section shows 

 a brown ring between the white scales of the bulbs, these bulbs should not 

 be sold. 



Stock suffering from the ring disease can be cured by putting the bulbs 

 in sandy soils, not freshly manured, with a deep lying ground water level, 

 where, with scarcity of nutriment and moisture, they can ripen early. 



The fact still remains to be mentioned that a phenomenon has been con- 

 fused with the real ring disease, which is very similar to it judging from its 

 habit of growth\ The cause is known to be a nematode {Tylenchus 

 Hyacinthi Pr.) which can wander into the scales from the leaves. In this 

 disease, however, a gall-like distension of the cells takes place, also the 

 formation of cork w^alls like little islands and other differences, as has been 

 described more in detail in the second edition of our manual. 



Springing of the Bark. 



In illustrating the ruptured bean plant (Fig. 42), we noticed that a 

 soft tissue mass had protruded through the gaping split in the cracked stem. 

 This is the new formation of bark tissue, which may be considered a re- 

 action of the organ to the wound stimulus and the decreased tension. Other 

 cases, however, occur in which matters are reversed, viz., that the increase 

 of bark tissue is the primary process and the splitting, the secondary one. 

 Such an increase in growth can arise from different causes. Hartig- con- 

 siders one of these to be the increase in size caused by a sudden isolation 

 of forest trees. He describes cases of hornbeams in a beech grove, where, 



1 Journal de la Soc. nat. et centrale d'Horticulture de France. April, 1881. 

 Sorauer, Zur Klarung der Frage tiber die Ringelkrankheit der Hyacinthen. Wiener 

 illustrierte Garlenzeitung, 1882. April number, p. 177. 



2 Hartig-, R., Das Zerspringen der Hainbuchenrinde nach plotzlicher Zuwachs- 

 steigerung. Untersuch. forstbot. Inst. Vol. Ill, p. 141. 



