186 VEGETABLE ORGANOGRAPHY. 



stem itself, causes an inequality in the facility with 

 which the sap penetrates the different sides of the 

 flower or fruit, and the less favoured sides often present 

 abortions. 



#d. The fecundation cannot take place upon all the 

 stigmata at once, and the fecundating vessels which go 

 from the stigmata to the ovules, do not carry the fovilla 

 to all of them at the same time. When the ovules do 

 not grow rapidly after fecundation, this inequality in the 

 period of fecundation does not cause any abortion ; but 

 if one or more of them grow rapidly, then they tend to 

 render the others abortive, either by attracting all the 

 nourishing sap, or by compressing or obliterating the 

 filaments of the pistillary or nourishing cord of the 

 other ovule. As these causes are connected with the 

 original structure of each species, the abortions which 

 result are nearly constant, as we clearly see in the Oak, 

 Horse-Chestnut, Lodoicea, &c. 



The unions of the seed with parts of the pericarp, 

 have already occupied our attention ; but I ought to 

 mention here the accidental union of them with one 

 another, a rare phenomenon, and of which I have as yet 

 only seen a positive example, shown to me by M. Hey- 

 land: it is that of two seeds of the Horse-Chestnut, 

 which were united together half-way. I mention this 

 fact, not only on account of its rarity, but because it 

 may lead to the explanation of another, more important 

 and less rare, viz. — the plurality of embryos in one seed. 

 This fact is frequent in different species of the Auranti- 

 aceae ; thus, the Orange has usually three or four, and 

 it is accidentally observed in some other plants, as in 

 Ardisia coriacea. Richard does not hesitate to regard 

 this plurality as monstrous. I should be inclined to 

 believe that it results from the incomplete union of two 

 or more ovules, the spermoderms of which united to- 



