IS 13.] Imperial Institute of France. 73 



appear. When the leaves are spiral, the number of angles of 

 the medullary case is equal to that of the leaves of which the 

 spirals are composed. Thus the medullary case of the lime has 

 four angles ; that of the oak, the chesnut, the bramble, the pear- 

 tree, almost all the fruit-trees, &c. has five angles, more or less 

 regular, because the spirals succeed constantly in fives. 



Grew and Bonnet alone seem to have been on the way of 

 these observations. The first had observed very various forms in 

 the medullary case, especially in that of the conical roots of 

 culinary plants ; but he did not observe the relation between 

 these forms, and the dispositions of the branches and leaves. 

 The second carefully examined vegetables with opposite, verti- 

 cillated, alternate, and spiral leaves ; but did not observe the 

 connection of these dispositions with the form of the medullary 

 case. 



M. de Mirbel has continued his researches into the structure 

 of the organs of fructification in vegetables, in which he has 

 been seconded with a zeal and intelligence that he takes a 

 pleasure in acknowledging, by M. Schubert, whom the Grand 

 Duchy of Warsovia sent into Fiance to complete his knowledge 

 of botany, which he was afterwards to teach in Poland. These 

 two botanists have examined all the genera of trees with needle- 

 shaped leaves, or the coniferous, one of the most important to 

 be known, on account of the singularity of its organization, of 

 the greatness of the species which it includes, and of the utility 

 of its products. Every body is able to distinguish, at the first 

 glance of the eye, the cedar, the meleza, the spruce fir, the 

 Scotch fir, the thuya, the cypress, the yew, the juniper ; but 

 though the botanists have studied with particular attention the 

 organs of reproduction of these vegetables, they are not agreed 

 about the characters of the female flower ; or to speak more 

 correctly, the greater m-mber are of opinion that the stigmata 

 of the spruce fir, the Scotch fir, the cedar, and the meleza, 

 have not yet been observed. In this respect, therefore, these 

 trees arc in reality cryptogamOus. MM. Mirbel and Schubert 

 go farther: they affirm that the female flower of the yew, the 

 juniper, the thuya, the cypress, &c. is not better known ; and 

 that all the genera of coniferous plants have a common charac- 

 ter, which has hitherto misled observers, and which consists in 

 the existence of a cup, not similar to that in the Bower of the 

 oak, but more deep, concealing entirely the ovarium, and con- 

 tracted like the neck of a bottle at its orifice. The female 

 flower enclosed in this case has escaped observation. In the 

 thuya, yew, juniper, cypress, oce. the cup is strait ; and by an 

 error, occasioned by the extreme smallness of the organs, the 

 orif'ee of this cup has been always mistaken for the stigma. In 

 the cedar, meleza, spTUCfl fir, and Scotch fir, the cup is re- 



