PHA NEROGA MS. ^ 2 ^ 



of an apical cell, but arises, on the contrary, in Gymnosperms from a luxuriant 

 growth of the layers of periblem of the root and from their splitting away towards 

 the apex, and in Angiosperms from a similar process in the dermatogen \ Even the 

 first rudiments of lateral structures, leaves, shoots, and roots, cannot be traced back 

 in Phanerogams to a single cell in the same sense as in Cryptogams. They are 

 first observable as protuberances consisting of a few or a larger number of small 

 cells ; the protuberance which is to form a shoot or a leaf shows, even when it first 

 begins to swell, an inner mass of tissue which is connected with the periblem 

 of the generating vegetative cone, and is covered over by a continuation of the 

 dermatogen. 



The normal JMode of Branchmg at the growing end of the shoot, leaves, and 

 roots, is, with few exceptions, monopodial. The generating axis continues to grow 

 as such, and produces lateral members (shoots, lateral leaf-branchings, lateral roots) 

 beneath its apex ; some cymose inflorescences appear however to be the result of 

 dichotomous branching. It is possible also that in Cycadeae the branching of the 

 stem and leaves may be dichotomous. The monopodial branching of the axes 

 is usually axillary ; /. e. the new rudiments of shoots appear above the median plane 

 of very young (but not necessarily the youngest) leaves, in the angle which they form 

 with the shoot, or somewhat above it. In Gymnosperms every axil of a leaf does 

 not usually produce a shoot ; sometimes (in Cycadeae), the branching of the stem 

 is reduced to a minimum. In Angiosperms, on the contrary, it is the rule that every 

 axil of a foliage-leaf {i. c. one not belonging to the flower) produces a lateral shoot 

 (sometimes even several side by side or one above another) ; but commonly the 

 axillary buds, once formed, are inactive, or develope only at later periods of vege- 

 tation. In addition to the above-mentioned cases of apparent dichotomy, there are 

 in Angiosperms only a few cases of actual or apparent extra-axillary branching, 

 which will be mentioned when discussing the characteristic features of this class. 



Phanerogams are distinguished from Cryptogams by an extraordinarily varied 

 and complete metamorphosis of members bearing the same name ; and this is con- 

 nected with the almost infinite variety in the mode of life, and the strict differ- 

 entiation of the physiological functions of these plants ; and the same is the case 

 with the differendation of tissues, which in Phanerogams greatly exceeds even that of 

 Ferns. In these respects also Gymnosperms assume an intermediate position 

 between Cryptogams and the rest of Phanerogams. 



What has now been said will serve to explain on one hand the distinction between 

 Vascular Cryptogams and Phanerogams, on the other hand the points in which they 

 agree, and the affinity of the two groups in their main outlines. In order, however, to 

 facilitate the comprehension by the student of the characteristics of the separate classes 

 of Phanerogams which are now to be described, we must in the first place keep in 

 view a few of their peculiarities, which have at present only been briefly touched upon, 

 and attempt to settle the nomenclature, which has become to some extent obsolete 

 and out of harmonv with the most recent theories. 



The Flower, in 'the broadest sense of the term, is composed of the sexual organs 

 and the axial structure which bears them. When the leaves which stand immediately 



See Hanstein, Bot. Abhandl. Heft I, and Reinke, Gottinger Nachr. 1871, p. 533. 



