128 Hislorical Sketch of Improvements in [Aug. 



term a naked seed, not only those fruits in which the integument, 

 to which the ovuhmi was originally attached by a point only of its 

 surface, has acquired so complete an adhesion to the proper coat 

 of the seed as not to be separable from it, but also every mono- 

 spermous pericarpium bearing a general resemblance to a seed, 

 and whose outer covering, though distinct from the nucleus, is 

 only ruptured after germination has commenced. Of these fruits, 

 improperly called naked seeds, Richard distinguishes two prin- 

 cipal kinds: 1. the akenium, in which the pericarpium is distinct; 

 and 2, the cariopsis, in which the pericarpium coheres with the 

 seed. 



Although an ovulum has not yet been found to be produced 

 without a covering, yet Mr. Brown has shown, that in Leon- 

 tice, the immediate effect of impregnation is to produce a swell- 

 ing of the ovulum without a correspondent enlargement of the 

 ovarium; in consequence of which, the ovarium is ruptured, and 

 a seed, provided with its proper integuments, is protruded, at the 

 base of which, when ripe, the withered remains of the ovarium 

 are visible. The peliosanthes Teta has also originally three cells, 

 each containing two ovula, but, soon after impregnation, from 

 one to three of these ovula rapidly increase in size, stifle the 

 others, and rupture the ovarium, which remains but little enlarged 

 at the base of the fruit, consisting of from one to three naked 

 berry-like seeds. In sterculia, the ovarium is thus ruptured in 

 the direction of its sutures, and the valves acquire the tbrm and 

 textun'e of leaves, to whose thickened margins the ovula continue 

 attached until they ripen. A somewhat similar instance occurs 

 in reseda, w hose capsule opens at top, at a very early period. 



Other anomalies from the usual economy of seeds are observ- 

 able. In the mangroves, rhizophora and Bruguiera, the embryo, 

 long before the seed is detached from its parent plant, pierces the 

 pericarpium, and acquires the length of one or two feet, and the 

 proper integument of the seed is absorbed. In eugenia, the in- 

 tegument of the seed is completely absorbed, even while the pe- 

 ricarpium remains entire. In some species of pancratium, cri- 

 num and amaryllis, the seed separates from the plant, and even 

 from the pericarpium before the embryo becomes visible, the seed 

 having a central cavity filled with a glairy fluid, in which the 

 embryo is afterwards formed, which in some cases does not be- 

 come visible unless the seed is placed in a situation favourable to 

 germination, so that we can regulate the direction of the radicular 

 extremity. In certain aroidese, especially in calladlum, the nu- 

 cleus of the seed is composed of a mass resembling the tuber of 

 a root, of an uniform structure, having neither cotyledon, plu- 

 mula, nor radicle, and frequendy with more than one germinating 

 point on the surface. Linn. Trans, xii. 143. 



?>. FLORAE OF DIFFERENT COUNTRIES. 



Germany. — Opiz has lately published, at Leipsic, an arrange- 



