234 MORPHOLOGY. 



trunk (adventitious buds) ; from these, as from the embryo, pro- 

 ceed perfect plants with axis and leaves, but, by reason of their 

 origin, without radicle extremity ; therefore, if they become inde- 

 pendent, they become possessed exclusively of adventitious roots. 

 Connected with the main axis these are called secondary axes ; 

 when annual, twigs or shoots ; when perennial, branches ; and the 

 kind of combination in general, the ramification of the plant.* 

 There are very few perfectly simple plants (of the second order) ; 

 most are compound, at least in this way, that their buds produce 

 flowers ; but as every inflorescence arrests the further development 

 of the axis, we may call those plants simple the axillary buds of 

 which are exclusively flowers. The mode of ramification is the 

 chief characteristic of the peculiar physiognomy of the whole plant 

 (the habit, habitus). There is no regularity in the adventitious 

 buds ; but the position of the axillary buds is conditioned by the 

 position of the leaves, and follows at once from this when all the 

 buds are uniformly developed. But this does not often take place, 

 since regularly appointed buds either remain wholly undeveloped, 

 or form only transitory flowers, and thus are the same as unde- 

 veloped buds, at least to perennial plants. Thus in Lemna no 

 terminal bud is formed, but only two lateral buds ; these usually 

 soon divide from the parent plant, and become developed in the 

 same manner, and so on. Viscum album forms a flower- bud in 

 every terminal bud ; and as the leaves, and therefore the buds, 

 stand in pairs upon the axis, the stem appears to be repeatedly 

 bifurcated. In very many, especially of the perennial, Monoco- 

 tyledons, it is regular for no axillary buds, except those growing 

 into inflorescence, to come to perfection ; thus, in most Palm- 

 stems, and the so-called arborescent Liliacece, Yucca, Aletris, &c. 

 The same occurs in some Dicotyledons, e. g., Carica, Tkeophrasta. 

 Further, the varying rapidity and force of development determines 

 peculiar forms. If the main axis is developed little or not at all, 

 in proportion to the secondary axes, the so-called caulis deliquescens, 

 the vanishing stem, is formed (as in Prunus spinosa) ; if all the 

 secondary axes are developed with proportionately equal force with 

 the main axis, the plant exhibits commonly a very long, ovate 

 shape (axis ramosus), as in the Lombardy Poplar; if the lower 

 branches are developed more quickly than the upper, so that all 

 the points lie in one plane, the fastigiate plant (axis fastigiatus) 

 results, and so forth. But the especially important point, as cha- 

 racteristic of the landscape, is the death of all the lower branches 

 in perennial plants, whereby is effected the so characteristic sepa- 

 ration of the tree into trunk and crown, or simple and ramified 

 axis. 



Finally, I have to mention here that the main axis very often 

 dies soon after it has become developed out of the embryonal con- 



* Inflorescence and fructification are really quite the same, namely, ramifications ; 

 inasmuch as the terminal shoots or twigs bear flowers, &c. 



