PHANEROCAMIA : FOLIAR ORGANS. 269 



shaped body, in the angles of the divisions of the leaves. In this little 

 body are especially developed the under side and the inner border of 

 the orifice (which does not increase much in size), so that the full- 

 grown pouch presents itself as a roundish and somewhat laterally 

 compressed body, which above is continuous by one angle with the stem, 

 while the other exhibits an orifice, which forms a little funnel projecting 

 inwards. The external orifice of this funnel is closed by a kind of 

 beard growing on the upper border ; the lower part of the internal sur- 

 face of the funnel is clothed with elegant hairs of various forms, but 

 very regularly arranged, while the internal surface of the pouch exhibits 

 peculiar hairs, consisting of two cells, each running out into a longer or 

 shorter arm. 



In leaves, as in plants in general, all forms are possible, and almost 

 all actually existing, strict stereometric forms excepted. The termi- 

 nology depends either on comparison with mathematical figures, or with 

 objects presupposed to be familiar in common life. We have no sci- 

 entific rule for this, esthetic tact alone must be our guide. But within 

 the limits of certain vegetable groups, certain circles of forms do exclu- 

 sively occur ; and, under the guidance of accurate observation, we can 

 here establish more definite modes of nomenclature, which, however, are 

 only valid for these definite groups. But this belongs to special botany. 

 Lastly, it is wholly useless to teach the learner all the individual expres- 

 sions, since most of them, from the facts that they are merely figurative, 

 and that their correct application depends upon the degree of tact of the 

 individual, are differently explained and applied by almost every botan- 

 ist. I have adduced a stupid instance of this in the first part, and hun- 

 dreds of similar examples might be collected in reference to almost every 

 plant from the definitions of different botanists, and there is nothing 

 left for the student but, for every author that he wishes to use, to 

 begin the whole matter over again, and learn what is the exact sense in 

 which he uses the expressions.* 



The most important point evidently would be the laying down of mor- 

 phological laws for the development of the forms of the leaf on one and 

 the same axis of one and the same plant, genus, family, &c. ; but nothing 

 has yet been done towards this. The following alone can be expressed 

 in very general terms : 1. The forms of the leaf low down on the pri- 

 mary axis are the simplest ; they exhibit gradually upward greater and 

 more manifold combinations, and return finally at the extremity to 

 greater simplicity. The secondary (lateral) axes usually begin in the 

 same way with imperfectly developed leaves (scales of buds), the forms 

 then becoming more complicated, and finally simpler again. The end of 

 the axis is here always known by the inflorescence. Both in the primary 

 and the secondary axes, the transition from the simpler earlier forms (the 

 cotyledons and bud-scales) into the variously developed leaves, is some- 

 times sudden, and sometimes very gradual through a number of interme- 

 diate forms. 



2. Leaves which are formed under ground are always more simple 



* If we went through the works of our most important systematists, we should, per- 

 haps, not find one single definition in which two different so-called technical terms are 

 not applied to the same fact ; and I believe that I am right in saying that all these 

 Latin and corresponding German descriptive terms mark no clear, and, in particular, 

 no botanical, definitions, but serve for description of his impressions, according to 

 the choice and skill of each individual, as well as any others which he might select ; 

 and to fill books or lectures with German translations of these Latin terms is a most 

 unconscionable waste of time. 



