71 



be obtained of Mr. Rau, Bethlehem, Pa., or Mr. Hervey, Taunton, 



Mass. 



53. Botanical ^^^%— Annual growth of Trees. — To the Journal 

 of the Royal Society of New South Wales the Rev. G. E. Tenison- 

 Woods contributes some interesting data in regard to the annual 

 growth of trees. He states that a blue gum tree {^Eucalyptus glob- 

 ulus)^ known to have been planted eighteen years previously, when 

 cut doAvn was found to have thirty-six concentric rings, /. e.^ two for 

 each year. As this tree, as well as E, obliqua and others, sheds 

 its bark twice every year, he concludes that the sap rises twice a 

 year in these trees. 



Sizes of Leaves and Colors of Elowers, — According to the Gard- 

 eners' Chronicle, M. Ch, Flahault, in the Annales des Sciences Natu- 

 rellesy brings forward additional observations to support his view 

 that, under equal conditions, the leaves of plants of the same species 

 are larger in proportion as we go northwards ; these relatively large 

 dimensions being due to the duration of light of relatively feeble 

 intensity. In cases where the chrophyll is formed in the absence of 

 light it must be formed at the expense of the materials stored up in 

 the tissues. The importance of these reservoirs of nutriment is still 

 greater in. the case of flowers. Thus, in the case of hyacinths, both 

 blue and red, M. Flahault found no difference in the color of the 

 flowers grown in the light or in the dark, the color being manufac- 

 tured from the stores of materials in the bulbs. 



Plant Hairs. — At a recent meeting of the Societe Botanique de 

 France, M. Poisson read a paper on '' Tlie Adaptive Character of 

 Plant Hairs," and stated that in most climbing plants, as Darwin 

 had shown with regard to the hop, Galium aparine and Rubus aus- 

 trails^ the ridges alone of the stem are furnished with stiff hairs 

 whose tips are bent downwards, while, in the intervals between the 

 ridges, on the upper surface of the leaves, and on the inflorescence, 

 etc., the hairs have a forward or horizontal direction. That these 

 hairs are adapted to enable the plant to climb, is, he considers, evi- 

 dent from the fact that in the dwarf varieties of the haricot beans, 

 which do not climb, these hairs have not a downward direc- 

 tion, and that in the Loasaceae and other families, it is the species 

 which climb that alone present this form of hair. Of course, there 

 are exceptions, such as Dioscorea, in which the leaves are glabrous, 

 and the stem hairs not bent downward. M. Poisson proposes to 

 turn to account the fact that, in the majority of cases, climbing or 

 twining plants have recurved hairs, by using it as a means of judg- 

 ing from incomplete herbarium specimens whether the specimen is a 



climbing plant or not. 



The April and May numbers of i:x\mtx\'^ Journal of Botany con- 

 tain mostly continued articles ; the new papers are, in the April 

 issue, " New Zealand Plants," by Dr, Berggren, and in the May, an 

 article on " Some Dorset Plant-Stations," by the Rev. W. Moyle 



Rogers. 



The Botanical Gazette for May contains notes on— ' New Species 

 of Potamogeton," by Thos. Morong; " Notulae Exiguae," by Dr. 



