286 MORPHOLOGY. 



3. Since in the uninterrupted development of buds they become 

 axes and leaves, there is nothing general to be said further on the 

 subject which has not been mentioned already under those par- 

 ticular organs. We must not, however, pass over buds with un- 

 interrupted vegetation, since they appear to hold a place as a 

 peculiar organ of the plant. In these we find that the external 

 (undermost) leaves are modified in peculiar ways, their forms ap- 

 pearing simpler than those later developed (higher up) from the 

 same bud. They may be termed in general bud-scales* (tegmen ta), 

 and, according to their various origins, tegmenta foliacea, as in 

 Fagus and JEsculus ; t. stipulacea, as in Carpinus, Corylus, and 

 Betula ; and, lastly, t. vaginalia, as in the bulbs of Allium, Lilium, 

 &c. Again, there is an essential distinction between the pro- 

 pagative and branch buds : the first are developed in a very solid 

 and fleshy manner, either in all their parts, as in the generality of 

 bulbs and bulblets, e. g. in Lilium candidum ; or in their axial 

 organs, as in the true tubers, e. g. in Solanum tubcrosum ; or 

 in the foliar organs, as in the so-called solid bulb of Allium 

 ursinum ; or, lastly, in certain determined parts of the axis, as in 

 the European Orchidece, and the Dahlias ; but in the branch 

 buds this fleshy development does not occur. On the other hand, 

 in the development of the latter buds to branches their bud- 

 scales fall away ; but in the propagative bud they gradually die 

 away from without inwards, and envelope the bud with a thinner 

 or thicker layer of dry membranes. 



Since it is most evident that bulbs are not roots, as many treat them, 

 but buds, there is no reason why the term tegmenta should not be applied 

 to those parts which, inasmuch as they are modified leaves, or parts of 

 leaves, and have essentially the function of shielding and covering that 

 part of the bud really capable of development, during the time of its rest 

 from vegetation, are clearly morphologically and physiologically the 

 same organs as the bud-scales. By applying the term tegmenta to these 

 also, we divest ourselves of one useless expression in terminology, which 

 is certainly again, ferula is a term wholly without etymological sense ; 

 and it is quite superfluous to discriminate between tegmenta and ramenta, 

 since both are parts of a leaf, or, more correctly, imperfectly, formed 

 leaves. 



b. Structure of the Bud. 



135. The structure of the bud has in part been sufficiently 

 discussed in the examination of the axis and leaf, but the several 

 peculiar kinds of bud require special treatment. We may, how- 

 ever, first make the general remark, that all buds consist originally 



* Link's (Elera. Phil. Bot. ed. 2. vol. i. p. 467.) comparison of the bud-scales with 

 the cotyledons is either very idle, if it means merely that both are foliar organs, like 

 other leaves, or distinctly wrong, since the cotyledons have the function solely of nou- 

 rishing the embryo, and the coats of the seed effect the protection during the rest 

 from vegetation, while the tegmenta have only the function of protection. The nutrition 

 is carried on by the axis on which the bud is situated. 



