24 OEIGIKAL ARTICLES. 



other. Tliis I have noticed in Berteroa ineana and Thlaspi arvensis^ 

 in whose ovnles the lower part of the cylindrical nucleus is thicker 

 than the ujiper, and the two integuments arise seemingly both at 

 once from the lower thickened part, at one time all round and at the 

 same height, at another time unilaterally. As in these cases, true 

 ovule-coats are developed on one side first, and not equally all round, 

 it does not seem unfair to infer the possibility of their appearance in 

 two distinct places or by two gibbi. The alternation of the two lips 

 of the o\T,ile-eoat of Taxus, with the two uppermost bracts, may be 

 understood to depend on the existence of more ample room for de- 

 velopment on the two sides where there are no bracts, than on the 

 other two, where the bracts come in contact with the ovule. It is well 

 known, that organs increase most in size and vigour in those parts 

 which are free and not interfered with by other organs, while they 

 are weaker and smaller, where they are pressed on by neighbouring 

 organs and deprived of nutriment. In the Abietineae this may be th& 

 cause of the bilobation of the ovule-coat, as the two teeth in. Ahies 

 excelsa, for instance, are on those sides of the ovule wliich are not 

 pressed on either by the axis or the scale. 



The second pai't of Baillon's proposition, regarding the flowers of 

 Conifers, is that they always arise from the axis and never from a 

 leaf or bract, or rather cai-pel. This is sho^^Ti to be erroneous as to 

 Abietinefe, at least by the monstrous larch described above. It is- 

 also excellently refuted by Baillon and Payer's own observations on 

 Pimis resinosa. As described by Baillon, the scales of Pinus pssinosa 

 are develoi)ed in the following manner. The scale appears first as a 

 small, dorsally compressed, broad boss in the axil of the bract. From 

 the first boss sj)ring three others, one central and two lateral. The 

 lateral bosses become broader, assume the form of auricles, cohere 

 externally, and, increasing mainly in width, are gradually converted 

 into an obliquely ascending lamina, the scale itself, which bears a 

 little above the middle in the median line, the subcentral boss, " the 

 organic apex of the axis," which axis produces no more appendages, 

 increases very little in size, and in the adult state, presents the forn> 

 of a hook bent inwards and downwards. On the upper surface of the 

 lateral -wings, towards their lower margin, which is turned towards 

 the primary axis, the ovules are, according to BaiUon, produced at a 

 later period. 



From this description it is evident that three distinct organs, all 

 differing in period of origin, can be distinguished, each of which i» 

 developed from that immediately preceding it. 



1. The axis which originates in the axil of the bract. 



2. The ear-shaped organs, which spring laterally from this axis, 

 and are called by Baillon the two lateral lobes. These ascend 

 obliquely and form the greater part of the scale, but are so situated 

 with respect to the minute axis, as manifestly to exhibit the character 

 of appendicular organs. They form two nearly i-ight angles Avith the 

 ascending axis, and spread out laterally and almoot horizontally,. 



