1885.] natural sciences of philadelphia. 365 



August 4. 

 Mr. Charles Morris in the, chair. 

 Nineteen persons present. 



Note on Quercus prinoides Willd. — Mr. Meehan exhibited a 

 series of fruiting specimens of branches of Quercus prinoides. In 

 some, the leaves were almost orbicular and obtuse ; in others nar- 

 rowly lanceolate or saliciform and acute ; others had lobed and 

 wavy edges, while others were quite entire. The plants were all 

 growing within a few feet of .each other, and the parent plants 

 were also all under the same conditions of environment, and were 

 at no distant date from one parentage. 



They were exhibited for two purposes — first, to show that 

 environment, as commonly understood, was not a main factor 

 in the origination of variation ; and secondly, to show that vari- 

 ation was independent of mere conditions of growth or sexual 

 peculiarities to which variation was sometimes referred. It 

 was, indeed, true, that young plants often had leaves varying 

 from those on the older plants, and plants or branches bearing 

 flowers of one sex would have characters varying from those of 

 another sex ; but these specimens were all fertile, and with young 

 acorns. There was no possible ground for any suggestion as to 

 different conditions in any sense, and the variations could be only 

 attributed to an innate and wholly unknown power to vary, which 

 science had so far been unable to reach. 



August 11. 

 Mr. Thos. Meehan, Vice-President, in the chair. 

 Eighteen persons present. 



On the Fruit of Opuntia. — Mr. Thomas Meehan exhibited a 

 series of specimens of an unknown species of Opuntia closely 

 allied to 0. Brasiliensis, showing a gradual change from the 

 joint or frond to the fruit. In one case there was the thin orbic- 

 ular frond; then a frond with a slight rounding and tapering 

 at the base; then one somewhat resembling a fruit, but v«t\ 

 much compressed, and with an abortive flower-bud leaving a scar 

 at the apex ; then another, but very much elongated and rtuted, 

 and with a perfect flower, though small ; and, lastly, the frond 

 reduced to an inch in length, pyriform, and with the perfect, 

 large yellow flower. He remarked that it could not be called 

 a novel point to make that the fruit of a cactus was simply a 



