288 MORPHOLOGY. 



acquainted with the native trees of our woods and forests. It ia 

 characteristic of these, that the young leaves, which subsequently 

 come to perfection in the more developed axis, are enveloped whilst 

 in the bud by stipules, which, soon after the development of their 

 leaf, fall away (stipulce deciduce), as in Liriodendron, or in leaves 

 or stipules of simple structure, of which the laminar portion is 

 abortive (tegmenta) : and there are varieties amongst these, so far 

 that either only the external or inferior leaves, or stipules, appear 

 as coverings of the buds, as in Fagus ; or the coverings of the bud 

 seem to be continued into the interior of the bud, but alternate 

 with leaves capable of perfect development, which lie between and 

 are covered by them, as in Acer. The coverings of the bud are 

 for the most part tough, and almost leathery; they are often filled 

 and coated over with resinous juices, and then mostly fall off in the 

 development of the bud, but they also occur thin and herbaceous 

 in texture, and even change quickly into dry thin membranes, which 

 mostly remain upon the plant : these last are seen in Pinus. 



The study of the bud is yet far from being complete : it requires much 

 comprehensive investigation. The best works which we possess upon 

 the subject are two essays of A. Henry.* But we want here the full 

 history of the development, without which nothing important can be 

 accomplished. The coverings of the bud are the undermost or inferior 

 leaves of the bud which is developing to an axis ; they are sometimes 

 many, sometimes few. Sometimes the internodes between the decidu- 

 ous (Fagus sylvatica) or persistent (Abies excclsa) bud-scales remain 

 undeveloped. All (?) plants here referred to develope yearly only one 

 simple bud, which was formed in the preceding year. A few plants 

 deviate from this rule in a manner which, after Linnaeus, may very 

 properly be called prolepsis. This occurs in some degree in AInus, in 

 which the under-leaves of the axillary buds are developed in the same 

 year that they are formed : hence the buds coming to development in the 

 spring are properly only terminal buds. Pinus deviates from the rule in the 

 most remarkable manner, in which all the leaves of the axillary and terminal 

 buds, gemma primaria, appear as bud-scales (tegmenta primaria\ and in 

 the next year, on the development of the bud, they fall away, all except 

 one little scalef, whilst the already formed rudimentary axillary buds, 

 (gemmce secundarice), which should only reach development in the third 

 year, are now developed ; on these secondary buds also the inferior 

 leaves are membranous bud-scales (tegmenta secundaria) ; and only the 

 two to seven of the upper leaves directly beneath the secondary terminal 

 bud, which almost always remain in a most rudimentary condition, 

 become developed into perfect leaves, and thus these, as the internodes 

 of the secondary bud do not develope, appear to arise, from two to seven 



* Nova Acta A. L. C. N. C. t. xviii. p. 1. and v. xix. p. 1 



f This is then of rather tough texture, and is merely the lower (in the bud con- 

 dition green) portion of the otherwise dry and membranous bud-scale. This is 

 remarkable for an interesting structure. The cells are all elongated, and in the middle 

 thickened by indistinctly porous deposits, almost to the filling up of the cavities. The 

 cells of the margins, on the contrary, where the bud-scale appears lacerated, exhibit a 

 very thin membrane, with a spiral striatiou of the utmost delicacy ; and the cells, which 

 appear on the border in the form of single hairs, tear, when pulled out, into a spiral 

 band, just like the hairs of the Mamittarier and Melocacti. 



