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The Prickly Pear.— The Ohio species of cactus, Opuntia 

 humifusa, has an interesting habit which seems to be a protective 

 measure against cold. At the approach of winter the flattened 

 stems lose their upright position and press themselves closely to 

 the surface of the ground. The stems lose considerable of their 

 moisture at the same time, becoming wrinkled, but not flaccid. 

 By the end of April they are again upright and distended. — Ohio 

 Natural is t. 



Plants of the High Andes. — At a meeting of the Lin- 

 naean Society of London, on April 4th, a paper was read by 

 Messrs. W. B. Hemsley, F. L. S., and H. H. Pearson, F. L. S., 

 on a small collection of dried plants made by Sir Martin Conway 

 in the Bolivian Andes in 1898-99. This collection contained 

 but forty-six species, but these were of special interest from the 

 great height at which they were found, i. c. between 18,000 feet 

 and 18,700 feet above sea-level. The highest Andine plants on 

 record were stated to be Malvastrum flabellatum, Wedd (one of 

 the mallows) and a grass, Dcycuxia glacial is } Wedd. — Gardening 

 World. 



Strange Partnerships. — If we look closely into Nature we 

 find many strange partnerships. Perhaps the strangest and most 

 interesting of all is that of plants living in partnership with in- 

 sects for their mutual welfare. The plant is a Mexican tree, 

 Acacia spliacroccphala, and its partner, a pugnacious species of 

 ant. The branches are armed with singular double thorns, from 

 which feature it is known as the Bull's Horn Acacia. These 

 thorns are very hard but hollow. At the base there is a soft spot 

 which is easily pushed in and makes a passage into the hollow of 

 the thorns. It is in these hollows that the ants live with their 

 heads filling up the holes. When an insect attempts to climb past 

 one of these the ant rushes out and destroys it, but does not, 

 as might be supposed, live on its prey. Its food is provided by 

 the plant in the form of little grain-like growths at the tips of 

 the pinnae, so that by this partnership the ants protect the plant 

 in return for food and shelter. 



