PROCEEDINGS OF SOCIETIES. 165 



investigated by him — each measured to scale and sketched accordingly. 

 Some families of plants he finds present great uniformity of figure and 

 size in their pollen, but on the contrary others are as notable for 

 diversity, even in what would seem closely related species. — '* Notes 

 on Algse found at Kerguelen Island by the Rev. A. E. Eaton," 

 by Prof. Dickie. Three new species are therein described, viz. : — 

 Sphacelaria corymlosa, Melobesia Kerguelena, and Ptilota Eatoni.* 

 Of a total number of sixty-five Algae recorded, sixteen belong to the 

 olive, thirty-four to the red, and fifteen to the green series. Nine 

 species seem to be peculiar to the island, and twenty-one, or about 

 one-third of the whole, are found elsewhere and on European shores. — 

 *' A List of the Musci and Hepaticee collected in Kerguelen Island by 

 the Kev. A. E. Eaton," by "William Mitten. This contains the names 

 of thirty-eight Mosses and thirteen Liverworts. Among the former 

 Bartramia Eatoni, and among the latter Tylimanthus viridis and 

 Balantropsis incrassata, are species new to science. — Mr. Carruthers 

 exhibited under the microscope the preparations of the Potato-fungus 

 made by Prof. De Bary, and gave an abstract of the results arrived 

 at by the latter in his recent investigation of the subject. As we 

 have reprinted the memoir of De Bary in full it is unnecessary to 

 recapitulate the subject here. Mr. W. G. Smith made some obser- 

 vations in support of his interpretation of the Fungus seen by him, 

 which had been controverted by De Bary, and the further discussion 

 of the matter was postponed. 



March I6th. — J. G. Allman, Esq., E.R.S., President, in the chair. 

 Mr. Van Voorst presented to the Society two volumes of British 

 Algse authentically named by Prof. Harvey.— Mr. A. W. Bennett made 

 some observations on the growth of the stalk of the Hyacinth. He found 

 that the greatest energy of growth is always in the lower portion of 

 the stalk, thus agreeing with most recorded observations on growth, 

 but otiering a contrast to the flower-stalk of ValUmeria. The following 

 papers were read : — " On the hygroscopic mechanism by which certain 

 seeds are enabled to bury themselves in the ground," by Erancis 

 Darwin. The seeds observed were those of several Grasses and of 

 Anemone montana, but 8ti;pa pennata was specially examined. This 

 has a strong awn, the lower part vertical and twisted with two knees, 

 and a long horizontal upper feathered portion. Moisture causes the 

 spiral portion to untwist and the horizontal part to revolve, the knees 

 disappearing and the whole awn becoming straight ; drought reverses 

 the process. In nature the flat feathered portion is readily entangled 

 in vegetation, and the seed rests vertically with its point on the soil. 

 When the spiral untwists with moisture, the horizontal part being 

 prevented from revolving, that motion is transferred to the seed, and 

 to this being added pressure on its point it becomes screwed into the 

 ground. With dryness and the reversal of the screw the seed is not 

 drawn out again, but curiously is thrust deeper down by additional 

 mechanism. Heat acts in the same way as moisture. The cause of 

 torsion as explained by Hildebrandt and Hanstein the author thinks 

 insuificient, and shows that the power resides in the individual cells 

 of the awn, which when isolated behave precisely as the whole awn 



* The diagnoses of these have been given in this Journal, pp. 50, 51, 



