224 MORPHOLOGY. 



through the whole period of vegetation ; these are succeeded by the de- 

 veloped internodes of the infloresence, only enduring in the latter part of 

 the vegetative period. In Zea Mays, the stem begins with a developed 

 internode, which soon dies ; this is succeeded by undeveloped internodes, 

 then developed, both enduring the whole period of vegetation ; then fol- 

 low again the undeveloped ones of the female inflorescence, only existing in 

 the end of the vegetative period. Chamccdorea Schiedeana begins with 

 undeveloped internodes, then follow developed ; both perennial. Nuphar 

 luteum begins with a developed internode, which soon dies ; then follow 

 undeveloped perennial internodes ; then one developed, appearing as a 

 flower-stalk, merely towards the close of the vegetative period. Lilium 

 candidum begins with undeveloped internodes which are perennial ; 

 then follow annual, developed internodes, &c. These examples might be 

 easily multiplied and completed. Some forms are characteristic of certain 

 groups of plants ; for instance, trunks with developed internodes in the 

 Cupuliferce, trunks with developed internodes in the fistular Palms, with 

 undeveloped internodes in the remaining kinds, stem with developed in- 

 ternodes in most of the Grasses, &c. Certain combinations are also cha- 

 racteristic ; for instance, perennial undeveloped, with annual developed 

 internodes, in all (?) Liliacece. But definite forms and combinations are 

 much more frequently found peculiar to single genera or species. Hitherto, 

 far too little regard has been paid to this condition of special regular se- 

 ries of developed and undeveloped internodes in the same axis. The 

 remarkable peculiarity of many genera and species, which, in germi- 

 nation, first form a developed internode, soon decaying again, and suc- 

 ceeded by undeveloped ones, has, in particular, been wholly overlooked. 

 Very different plants furnish examples of this : Zea Mays, Briza max- 

 ima, Phormium tenax, Nymphcea, Nuphar, &c., and at least very fre- 

 quently Avena sativa, and Hordeum vulgare. In the axis with unde- 

 veloped internodes, frequently, and the oftener when it has commenced 

 by a developed internode, the death of the single joints progresses gra- 

 dually upward, so that the axis, even when perennial, never attains any 

 considerable length; e.g. in Iris, bulbous plants, and most subterraneous 

 axes (rhizomd) with undeveloped internodes. 



Here, however, I must enter somewhat more minutely into the course 

 of development of these forms of the axis. It has already been men- 

 tioned ( 74.) how every form must be produced solely from the ar- 

 rangement of the newly developed cells and their subsequent expansion. 

 On this depends all structure of axes. In the embryo, the upper end, 

 from which the axis is developed (the terminal bud), more or less resem- 

 bles a hemisphere, or a blunt cone. In this part chiefly goes on the 

 formation of new structure, and it always retains its general form. In 

 the axes with undeveloped internodes only, if they expand very much in 

 breadth, does it naturally acquire a larger base, and then becomes, ac- 

 cording to its specific peculiarity, either shorter and more blunt (as in 

 most subterraneous axes), or longer and more acute. The process of 

 formation which here takes place has not, indeed, by any means been 

 so accurately investigated as is necessary ; but still much may be per- 

 ceived with tolerable clearness. An eye only moderately accustomed to 

 such matters readily discovers in a plant the situations where an active 

 process of cell-formation is going on, in the apparently structureless 

 condition of the yellowish, almost fluid masses (first stage) , the situa- 

 tions where the cell-formation has ceased, in the distinct, indeed, but 

 very delicate, cellular tissue (with more homogeneous contents), which 



