LECT. XI.] CAULINAR AND FOLIAR APPENDAGES. 607 



stipule is also liable to undergo transformations : 

 it becomes a tendril in Smilax, and a prickle in the 

 Acacia. 



b. The braete, or floral leaf (bractea), is a 

 foliaceous appendage, which appears in the vici- 

 nity of the flower ; distinct from the perianth,, and 

 in some instances exactly resembling the proper 

 leaves, but in others differing from them both in 

 form and in colour *. The spathe, a membranous 

 sheath which encloses the flowers of the Irises 

 and some other plants before they blow ; and the 

 involucre, a foliaceous appendage situated at the 

 base of the umbel in umbelliferous plants, are 

 modifications of the bracte ; but as they shall be 

 described amongst the proper appendages of the 

 flower, I shall at present confine my remarks to 

 those bractes which have more of the foliar cha- 

 racter. Bractes, in this limited sense of the term, 

 differ in form, colour, situation, and duration. 



The form and aspect of the bracte, as I have 

 already stated, is frequently that of the proper 

 leaf; and its diversities, therefore, are designated 

 by the same terms which are employed to distin- 

 guish those of the leaf. In some instances there 

 is a gradation scarcely perceptible from the proper 

 leaves to bractes, as in Purple-topped Clary, 

 Salvia Horminum, Alpine Bartsia, Bartsia alpina, 



* " Bractea dicitur folium florale cum colore et figura recc- 

 " dit a ceteris." Phil Hot, 84/2. 



