H. BOTANY AND HORTICULTURE. 363 



They as a consequence appear upon the basidia or spore-bear- 

 ing spicules at the rate of 100,000 ever}^ minute ! Gardener'' s 

 C hronide, October lQ-2Z,lQlb. 



GLANDS OF CAENIVOKOUS PLANTS. 



Those plants which possess the peculiar power of absorb- 

 ing* and dio-estino; nitrosfenous substances presented to their 

 leaves are principally insectivorous plants, belonging to the 

 genera Drosera^ Pingidcula^ Dioncea^ and Utricidaria. In 

 all these, minute glands exist imbedded in the surface of the 

 leaf, reddish-purple in Dioncea^ and giving a red tinge to the 

 leaf. They are smaller than stomates. Monthly Micro scop- 

 icaUournal^ January, 1876. 



THE POTATO DISEASE. 



For more than thirty years our potato crops have been 

 systematically destroyed by two virulent fungi, viz., Pero- 

 nospora infestans and Fasisporimn Solani: these two para- 

 sites almost invariably work in company with each other; 

 they suddenly appear for a few weeks, destroy our crops, 

 and vanish for ten or twelve months, then reappear and re- 

 peat the work of destruction. Mr. Worthington G. Smith 

 has shown how these fungi hide and sleep through eleven 

 months of the year. He has kept the resting spores of both 

 parasites alive, artificially, in decayed potato leaves, under 

 water, in moist air, and in expressed juice of horse-dung; it 

 is fair to conclude that the resting spores hibernate naturally 

 in the same manner. The seat of danger from both parasites 

 is clearly in dung-heaps and decaying potato plants. In July 

 last Mr. Smith obtained the oospores, or resting spores, by 

 keeping potato leaves and tubers constantly moist, and pre- 

 served the material in which the resting spores were present 

 in sealed bottles, containing more or less pure water, or ex- 

 pressed juice of horse-dung diluted with water, quite in the 

 dark as to what the results might be. After waiting with 

 considerable anxiety, and dividing the material to insure 

 asrainst loss, and keeping it constantly moist and in the dark, 

 and under examination every day for over three months, 

 during the latter stages of growth he detected the following 

 changes : Many of the resting spores increased in size to twice 

 their original dimensions during the first nine months, chang- 



