344 Linnean Society. [Nov. 21, 



is fleshy, of equal substance, not very thick, and generally of a 

 reddish -yellow or orange colour. In the Tovomitece it is slit upon 

 the dorsal side from top to bottom, the fimbriated edges overlapj^ing 

 each other, so that when opened out, it appears like a flat sheet with 

 the seed attached in its centre. In the Garciniece the arillus is much 

 thicker, of pulpy or mucilaginous substance, generally edible, and 

 quite entire, as in the Clusiea. The nature of this outer covering 

 in the two last tribes cannot be questioned, and it is fair to conclude 

 that the precisely analogous development in the Clusiea is also a 

 true arillus. It is however essential to determine this point beyond 

 cavil, because in the HypericacecE, Marcgraaviaceee, and other orders, 

 it has been held to be a thickened epidermis of the testa, while in 

 the MagnoliacecB it has been assumed to be the testa itself. In the 

 latter family, where the seeds are suspended by long funicular threads, 

 it forms a very conspicuous development, under the form of an entire 

 fleshy scarlet- coloured covering, precisely like that of Clusiece, and 

 where in like manner within it, on one side, is seen proceeding from 

 the base to the apex a flattened raphe, whose upper extremity is lost 

 in a fungous spot filling the cavity of a distinct aperture pierced 

 through the osseous shell, which by most botanists has been con- 

 sidered to be the testa, but which by some has been held to be the 

 inner integument of the seed, called tegmen by Mirbel, and endopleura 

 by DeCandolle. Endlicher was the first to suggest this idea, 

 which he expresses ambiguously, stating that the seeds of the 

 MagnoliacecB have in most cases " an external fleshy integument 

 covering a crustaceous testa, with a raphe situated between it and 

 the testa, and terminated by a chalaza on the summit, but that 

 sometimes there is no outer integument, the raphe in such cases 

 existing between the testa and endopleura." Mr. Miers considers 

 that this misapplication of the term chalaza (a name that should be 

 confined to the peculiar thickening of the inner integument where 

 it unites with the raphe, around the point where all farther trace of 

 the continuation of the nourishing vessels ceases), where evidently 

 it has been confounded with the diapyle, has probably led to the 

 error of regarding the true testa as the tegmen of the seed. Dr. 

 Asa Gray, however, in his ' Genera of the United States,' amplifies 

 this suggestion of Endlicher in unequivocal terms, stating that in 

 Magnolia the seed has no arillus, and he designates as the testa the 

 external scarlet covering which preceding botanists call arillus, 

 while the hard crustaceous shell called testa even by Endlicher, is 

 there denominated tegmen. This he infers from the fact of having 

 observed spiral vessels in the placentary attachment of the ovules, 



