BOTANICAL SUBJECTS. 207 



or finally may disappear altogether congenitally as if 

 they had never been there. 



In Spergularia it is evident that the so-called sti^Dules 

 are nothing but bud-scales. In " Nature," of 5th Sept. 

 1887, V. 18, p. 507, Prof. Alex. Dickson specially calls 

 attention to those of >S'. marina. He says the stipules 

 are free from the petioles, and by connation become 

 interpetiolar. "Lastly (and this is the important 

 point), these stipules are united to each other round 

 the bacJis of the petioles, so that a sheath is formed 

 completely surrounding the axis and the two leaf- 

 bases. This connation of stipules round the backs of 

 the petioles is very interesting, as being a rare phe- 

 nomenon." It is interesting indeed, for it shows us 

 plainly that the stipules of Spergularia are no other 

 than bracts or bud-scales to the leaves. And, as a matter 

 of fact, in Syme's " Engl. Bot.," V. 2, pi. 256, these 

 same interpetiolar stipules are higher up the stem 

 shown as bracts of the flowers. In Spergtdaria marina 

 the stipules by connation form at the node a sort of 

 protecting cup or involucre to the young leaves and 

 terminal bud. The only other case of this kind that 

 Prof. Dickson could find was in Astragalus, mentioned 

 by St. Hilaire in his Morphologie. 

 (c.) That stipules may also be considered as portions or lobes 

 of the leaf -blade left behind, connate with the stem 

 when the leaf has become petiolate, that is, when the 

 blade /nas retired towards the apex of the leaf. The 

 potato-leaf has many of these detached bits or lobes on 

 the leafipetiole. Any pair of these might be transformed 

 into stipules, if the petiole were shortened up to their 

 level. In fact, Liudley calls the appendages on the 

 petiole of Pyrus communis stipules, but they are so 

 high up that one would be justified in considerino- them 

 as atrophied leaflets, on their way to becoming stipules 

 as in Hardenbergia (Figs. 24 and 25), more especially 

 as this genus (Pyrus) has both simple and pinnate 

 leaves. 

 Then Salix fragilis, as shown in Nicholson's " Encyclop. 

 of Hort.," shows the leaves as trifoliolate, without petioles. The 



