498 Berry: Origin of Stipules in Liriodendron 



In the growth of young and vigorous shoots in the spring time, 

 where there is excessive, or at least a full supply of nourishment, 

 and where the necessity of protecting the unfolding leaflets is more 

 imperative, comparatively immense stipules usually occur ; one of 

 these (nat. size) is figured on Plate 42, Fig. 4, in order to show 

 its venation. 



Still another form sometimes assumed by stipules is shown in 

 Fig- 7, on Plate 42, reminding one of the curious stipular append- 

 ages on some of our magnolias. All degrees of coalescence occur 

 from forms barely united to those united for about half their length 

 like the one figured ; we have specimens one-third larger than this. 



Figs. 10 and 11 on Plate 42, show the curious stipular forms 

 which occur on Magnolia obovata Thunb. and Magnolia conspicua 

 Salisb. the only two species which I have had an opportunity of 

 observing. They form large bud scales, affording effective pro- 

 tection for the tender unfolding leaves. In the youngest shown 

 (Fig. 10), they are many times the size of the tiny leaflet they bear, 

 while Fig. 1 1 shows a larger leaflet. 



On comparing this form with those forms of adnate Lirioden- 

 dron stipules shown on Plate 42, Fig. 7, it will be seen that the 

 addition of a petiole with a small leaflet at its summit would make 

 them identical with the magnolia specimen, the venation too is al- 

 most identical, that in Magnolia being somewhat finer and more 

 reticulate ; as the Magnolia leaves become older the wings sepa- 

 rate along the petiole and fall off. These stipular wings become 

 particularly significant when we consider that Magnolia is so 

 closely related to Liriodendron, and has several species with basilar 

 lobed leaves. Magnolia, as we should naturally expect, is found 

 in older strata than Liriodendron and there is no doubt of their 

 community of descent from the same primitive form. It does not 

 seem to me to be necessary to make any further comments on 

 the foregoing; the figures tell the story, and no more perfect 

 series of forms, each slightly removed from its predecessor, could 

 be desired : in fact we are surprised to find the evolution of stip- 

 ules in this genus which must have occurred in the Cretaceous 

 period, so well portrayed and epitomized after so long an interval 

 of time. 



Passaic, N. J. 



