l8 9i-l Abyiormal Phyllotaxy. 165 



character of these whorls, which at present is no longer shown 

 by the petals and stamens. In fig. 17, the figure given by 

 Gray is repeated with certain variations, in order to call at- 

 tention to the peculiar position of the single pistil-leaf. This 

 leaf should fall opposite one of the stamens of the outer 

 whorl. As a matter of fact, however, it is opposed to a sta- 

 men belonging to the inner whorl in the flowers examined. 



Fig. 18 represents a subterranean bud of the twin-leaf, col- 

 lected Feb. 15th with a few scales removed in order to show, 

 at a, the bud from which is to develop the flowering bud two 

 years hence. Fig. 19 shows the same bud after the removal 

 of all the scales, in order to show the flower bud of the next 

 season, surrounded by the leaves of the same season. Fig. 20 

 presents a view of this flower bud after the petals have been 

 forcibly spread apart, showing the petals and stamens. 



Rkamnus lanceolatus. — The branches of many shrubs near 

 Dayton, Ohio, showed the leaf arrangement indicated in fig. 21, 

 which may be briefly characterized as consisting of decussat- 

 ing dimerous whorls of leaves, in which the leaves, apparently 

 belonging to the same node, are not strictly opposite to each 

 other, but are separated by a more or less pronounced inter- 

 val. This interval is in most cases not large enough to alto- 

 gether destroy the effect of decussating whorls as just de- 

 scribed. The same plants often show a typical two-fifths 

 phyllotaxy. As a rule species of Rhamnus are described as 

 possessing an alternate arrangement of leaves. 



Fraximcs. — A twig collected at Granville, Ohio, is repre- 

 sented by fig. 22, but only one-fourth of its natural size. 

 Here a branch has divided dichotomously, between the nodes 

 A and B f but that the dichotomous character was already 

 developed at a much earlier period is shown by the develop- 

 ment of four leaves at the node A ; the median two leaves 

 should have met at the centre of the compound stem at this 

 locality, but they have been crowded towards the exterior so 

 that both appear in the figure here presented. That the 

 dichotomous character was developed at an even earlier stage 

 ls shown by the position of the upper scales of the winter bud. 

 The effect of this irregularity (best seen at A, upon the suc- 

 ceeding nodes 5, and C 9 ) is to increase the interval between 

 the leaves belonging to the same node, already shown at A. 



This interval again diminishes at the node Z7, and ceases at 

 node E in one branch and at node F (not figured) in the 



