The Nature and Origin of Stipules. 21 



described by Professors Lesquereux and Ward is mentioned, and 

 the probability suggested that we have here an explanation of the 

 origin of the stipules of Liriodendron Tulipifera L. in the same 

 manner as that indicated for those of Platanus occidentalis L. by 

 Professor Ward. The presence of an unwinged portion of the 

 petiole next to the blade in what is evidently the mature form of 

 the leaves of Liriophyllum , and its absence in the immature ones 

 is mentioned as tending to confirm the theory. 



In commenting on this paper, the Botanical Gazette (19: 515, 

 1894) says, " The phyllopodium is to be regarded as an axis 

 which has a tendency to develop wing-like appendages at any por- 

 tion, notably, of course, in the epipodium. If stipules are 

 branches of the hypopodium their origin has simply to do with 

 the branching of that part of the phyllopodium, without an}' refer- 

 ence to the method of winging found in other regions." 



Lubbock. Sir John. — On Stipules, their Form and Function. Pt. II. 

 Jour. Linn. Soc. Lond. 30 : 463-532. 1894. 



This paper is a continuation of the author's former publication. 



The presence of stipels in Sambucus Ebulus L. is noticed. The 

 membranous protective margins of the sheath in Thalictrum 

 aquilegifolium L. and the " membranous stipular processes at 

 each trifurcation of the lamina " are mentioned, the latter "ap- 

 pearing to differ somewhat in their origin from the primary 

 sheath." In treating of Ranunculus aquatilus L., the author 

 says, " The terminal bud is enclosed by the stipules of the two 

 uppermost expanded leaves. The developing leaves push their 

 way out at the apex of the stipular sheath. Similarity of condi- 

 tions have therefore developed in the aquatic Ranunculacese, an 

 arrangement very similar to that of the Potamogetons." 



The following remarks are of particular interest : " In Mag- 

 nolia glauca L. the winter bud is covered by a pair of connate 

 stipules adnate to a petiole that is less than half their length. 

 Succeeding leaves are perfect, and the stipules are two or three 

 times as long as the petiole, the free portions being connate by 

 both edges, like a candle extinguisher, over the bud, so that the 

 leaf appears to spring from the back. As the_y are adnate to the 

 petiole, there is some reason to assume that the stipules once 

 formed a sheath pure and simple to the leaf of some ancestral 

 form." 



Annals N. Y. Acad. Sci., X, April, 1897.— 3. 



