BIOLOGY. 333 



dinary root-parasitic plant, of the region at the head of the Gulf 

 of California. It had been brieflj' noticed before as a new genus, 

 allied to the rare Mexican CoraUophi/llum (Kunth), or Lennoa 

 (Lexarza), and to the little-known Calitbrninn Pholisma (Nuttal).- 

 These strange 2)lants, though justly regarded rather M(jnotro- 

 paceous than Orobanchaceous, are still obscure. Growing in a 

 sandy desert, almost covered by the sand in which it lies, this 

 plant was found by its discoverer, Col. A. B. Gray, to foi*m a con- 

 siderable part of the sustenance of the Papigos Indians. It is said 

 to be XQvy luscious when first gathered and cooked, resembling in 

 taste the sweet potato, but far more delicate. 



Absorption of Carboiiic Acid by Plants. — M. Boussingault has 

 recently made some experiments, reported in vol. Ix., " Comptes 

 Rendus,'' on the absorption and assimilation of carbonic acid by 

 leaves exposed to sun-light. His results are as follows : 1. Leaves 

 exposed to the sun in pure carbonic acid do not decompose this 

 gas, or, if they do, it is with extreme slowness. 2. Leaves ex- 

 jjosed in a mixture of carbonic acid and atmospheric air rapidly 

 decompose the former gas ; oxygen does not seem to interfere iu 

 the phenomenon. 3. Carbonic acid is rapidly decomposed by 

 leaves when that gas is mixed with either hydrogen or nitrogen. 

 The author has pointed out some analogies of these phenomena to 

 the slow combustion of phosphorus under certain circumstances ; 

 thus, phosphorus 2Jhi'Ced in pure oxygen does not become lumin- 

 ous, and does not burn, or, if it does, burns witli excessive slow- 

 ness ; in a mixture of oxygen and atmospheric air, it burns rapidly ; 

 it also burns when placed in oxygen mixed with hydrogen, nitro- 

 gen, or carbonic acid. Phosphorus, which does not burn in pui'e 

 oxygen at an ordinaiy pressure, becomes combustible when the 

 gas is rarefied ; and M. Boussingault found that, similarly, a leaf 

 placed in rarefied pure carbonic acid decomposed the gas and 

 evolved oxygen. See also vol. Ixi., " Comptes Rendus," for a con- 

 tinuation of his experiments. 



The Gigantic Sequoia. — M. De Candolle, President of the Lon- 

 don International Horticultural Exhibition, held in May, 18G6, an- 

 nounced that a recent very exact measurement had been made of 

 the diameter of the trunk of one of the gigantic Sequoias of Cali- 

 fornia. The tree was the base of the " Old Maid," the stump of 

 which now serves as a dancing floor ; the measurement was made 

 by Mr. De La Rue and his assistant, on a slip of paper stretched 

 across the whole diameter of the section (26 feet 5 inches, at 6 feet 

 from the ground) , and the rings were carefully counted and marked 

 on the sli}}, — on one semi-diameter 1,223, on the other 1245; the 

 mean 1,234, — making the tree about 1,225 yeai's old. 



Batting of Fruits. — M. C. Davaine has presented to the French 

 Academy of Sciences a note on the " Rotting of Fruits," in which 

 he states that the natural rotting of fruits is ordinarily due to the 

 development of the microscopic fungi, Mucor mucedo and Peni- 

 cilbim glaucum. • The thicker the ejiidermis of a fruit, the longer 

 it will keep. The author points out the difference in the jirogress 

 of the change under the influence of the two fungi ; that produced 

 by Mucor being much more rapid than that set up by PeniciUum. 



