POSITION IN RESPECT TO TIIK BRACT AM) AXIS. 



237 



in passing from one cycle to the next ; — which is rather describing 

 the anomaly in other words than explaining it. 



443. Whether we regard the floral circles as decussating verticils, 

 or as cycles of alternate leaves in some way altered as to their suc- 

 cession, we cannot fail to discern an end attained by such arrange- 

 ment, namely, a disposition of parts which secures the greatest econ- 

 omy of space on an abbreviated axis, and the greatest freedom from 

 mutual pressure. 



444. Position of the Flower as respects the Axis and subtending Bract. 



All axillary flowers are situated between a leaf and the stem, or, 

 which is the same thing, between a bract, and the axis of inflores- 

 cence. These two fixed points enable us to indicate the relative 

 position of the parts of the floral circles with precision. That part 

 of the flower Which lies next the leaf or bract from whose axil it 

 arises is said to be anterior, or inferior (lower) : that which is dia- 

 metrically opposite or next the axis is posterior, or superior (upper).* 



It is important to notice the relative position of parts in this re- 

 spect. This is shown in a proper diagram by drawing a section 

 of the bract in its true position under the section of the flower- 

 bud, as in Fig. 358 : the position of the axis is necessarily dia- 

 metrically opposite, and its section is sometimes indicated by a dot 

 or small circle. In an axillary flower with the parts in fours, one of 



* As if these were not terms enough, sometimes the organ, or side of the 

 flower, which looks towards the bract, is likewise called exterior, and the organ 

 or side next the axis, interior ; but these terms should be kept to designate the 

 relative position of the members of the floral circles in aestivation (494). 



FIG. 356. Diagram of a Cruciferous flower (Erysimum); i 

 bract is abortive in this, as in most plants of this family.) 



FIG. 357 Diagram of a flower of a Rhus, with the axis 

 relative position of parts. 



FIG. 358. Diagram of a flower of the Pulse tribe : a, the I 



, the axis of inflorescence. (The 

 a, aud the bract, 6, to show the 

 xis, aud t), the bract 



