H. BOTANY AND HORTICUia'URE. 355 



iments, made at their gardens, to determine the effects of va- 

 rious fertilizers (mineral manures, ammonia salts, and nitrates) 

 upon different species of plants. Aside from the results pos- 

 sessing an economic value, certain conclusions are drawn of 

 a more scientific nature, in relation to the inducement of spe- 

 cific changes. No absolute change in habit was in any in- 

 stance observable, the eftect of the manures being simply to 

 enhance the vigor of growth, or the reverse, and more decid- 

 edly in the leaves, stem, etc., than in the flowers or fruit. 

 Nothing favored the inference that, by the agency of any 

 manure or vicissitude of climate, any change that would be 

 deemed of specific value could be artificially induced. On 

 the contrary, it would appear, as all other evidence yet ob- 

 tained shows, that " specific " character is not influenced by 

 external conditions, but is an innate quality transmitted by 

 hereditary descent. Jour. Hort. Soc.^ London^ January Y, 

 1873,124. 



FLOEA OF THE ISLAND OF ST. PAUL. 



The island of St. Paul, in the Indian Ocean, is believed to 

 contain the smallest phanerogamic flora in the world, there 

 being really only two indigenous species, although seven oth- 

 ers have been found, six of them grasses and one a sedge. 

 The two native species referred to belong to the genera Plan- 

 tacjo and Sagiiia. IS A, July 1, 1872, 253. 



eisler's reseaeches on evapoeation feom plants. 



The following propositions are presented by ]\Ir. E. Risler, 

 as the results of his researches on the evaporation from plants : 

 Evaporation from plants is not lessened when the surround- 

 ing air is saturated with aqueous vapor. Absorption of the 

 vapor in the air by the leaves has never been observed. Plants 

 in general evaporate but very little during the night-time. 

 All plants evaporate more in the sun than in the shade. With 

 luzerne, the quantity evaporated in the sun is four times as 

 great as in the shade, even when the difference in tempera- 

 ture is not very considerable. Thus the direct influence of 

 light, independent of its heat, is demonstrated. The yellow 

 rays of the spectrum are most active. With Indian corn, the 

 difference of evaporation in sun and shade is still larger than 

 with luzerne, while some plants are much less influenced ; the 



