190 REVIEWS. 



notes that the vernation of the leaves is involute in Pyrus, 

 but not in Cydonia, Mespilus, and Aria; that the cottony- 

 leaved varieties, no less than the smooth ones, are glabrous 

 in the seedling stage ; that all varieties of the common Pear 

 blossom at Paris whenever, in the month of April, the mean 

 temperature reaches about 10° Centigrade, without perceptible 

 difference between the earliest and the latest-ripening varie- 

 ties ; that the aestivation of the corolla is convolute in Cydo- 

 nia, but imbricate in the Pear, although ordinarily quincuncial 

 in other Pomacece (but in the two diagrams of Pear-flowers 

 on Plate A, one has the quincuncial, i. e., in our view typically 

 imbricative aestivation of the corolla ; in the other, there is 

 only one wholly outer and one inner petal, — a combination of 

 the quincuncial and the convolute modes which often occurs, 

 but which need not be taken as the type of imbrication) ; that 

 there are two types as to size of the corolla in the common 

 Pear, the smaller flowered type comprehending most of the 

 cultivated varieties ; that the odor of Pear-blossoms is rather 

 disagreeable than otherwise, in contrast with those of Mains, 

 which are sweet-scented. Moreover, the anthers in the Pear 

 genus are tinged with violet ; those of the Apple genus are 

 yellow. 



As to the morphology and development of the gynsecium, 

 Decaisne reproduces in full the note which he published in 

 the " Bulletin of the Botanical Society of France " in 1857. 

 From his investigation it appears that the five carpels in their 

 early development are free and distinct in the concave centre 

 of the flower ; that at a later stage, when the concave recepta- 

 cle has become much deeper, a cellular tissue develops from 

 its base and inner face, moulds itself around and over the car- 

 pels, so as separately to envelop them, except at their inner 

 angle, while it carries up the petals and stamens, and forms 

 the perigynous disk upon which they are inserted ; this forms 

 the co7'e or central part of the flesh of the fruit, which we 

 have always regarded as receptacle, never ceasing to protest 

 against the still prevalent notion (continued in the latest gen- 

 eral works), that the cartilaginous or bony " cells " are " en- 

 docarp." But, while we were disposed to regard the whole 



