THE LEAF. 



195 



ferous scale finds its replica in the curious outgrowth 

 (representing the tip of one of the next pair of leaves) 

 occurring in the upper part of the aclaxial surface of 

 the fleshy recurved leaf. 



" With regard to the physiological meaning and 

 cause of the abnormal condition of the piece of shoot, 

 the equilibrium of the whole has evidently become 

 upset, possibly by the presence of a fungus, which has 

 been ascertained to be present.* The axillary shoots 

 have been stimulated to an exceptional degree and 

 mode of development, but the reason for the particular 

 forms which they have taken is obscure. 



" At any rate, the phenomenon of the recurved leaf 

 and its mode of origin lends strong support to the 

 prevailing view of the morphological nature both of 

 the ovuliferous scale of Abietineae and of the 6 needle ' 

 of Sciadopitys. For it indicates the existence of a 

 tendency in the Coniferse for the first two leaves of 

 an axillary shoot to unite by their adaxial margins to 

 form a siugle dominant axillary foliar organ. 



" The abnormal shoot under discussion affords, 

 further, a powerful substantiation of the view that 

 teratological phenomena are often of great value in 

 throwing light on the nature and origin of otherwise 

 obscure structures. "t 



16. Fusion of Bracts. — The involucral leaves of a 

 species of hare's-ear (Bupleurum junceum) have been 

 seen united into a saucer-shaped structure. 



17. Suppression of Foliar Organs. — In some Legu- 

 minosas, e.g. Phaseolus vulgaris and Vicia Faba, a 

 leaflet occasionally vanishes completely. 



Bracts tend abnormally to disappear sometimes, as 

 was observed by Buchenau in the case of certain 

 two- to three-spurred, flowers of Tropseolum majus. 

 The absence of bracts is a normal feature in the 

 Oruciferae. 



* Mr. G. Massee investigated the shoot for this purpose, 

 t Worsdell, 1 New Phytologist,' vol. xiv (1915), pp. 23-26. 



