Organizaiio7i in Phcenogamous Plants, 185 



belongs. The leaves are arranged in the customary spiral 

 direction, even to the extreme summit, and no one leaf implies 

 in the slightest degree an adaptation to the female part more 

 than another (fig. I). The axis, as is customary, terminates 

 here also in a small protuberance (the 2)unctwn vegetationis of 

 Wolff'), and this is the nucleus of the ovule. Thus the axis 

 forms the second antagonistic power [differenz) of the plant, 

 forming as it does the female portion, and we are now in a 

 condition to perceive that impregnation and fructification 

 consist in the conjunction and balancing of the two most im- 

 portant antagonistic forces the plant possesses, viz., those of 

 the horizontal and vertical structure. 



We will however calmly prosecute the course of our inves- 

 tigation further. The terminal portion of the axis constitutes 

 therefore the nucleus of the ovule, and is the onlij actual and 

 never-failing portion of the entire female organ, whilst all 

 other parts are or may be partially deficient; some in this 

 plant, some in that. Now this end of the axis is frequently 

 found bent, so that its point becomes reflected upon itself 

 (ovulum anatropum\ and adheres to that portion which retains 

 its proper direction [r'apJie), a process which may be easily 

 recognised on inspection. In this condition {ovulum ex nucleo 

 nudo constans) we find the ovule in many families, as for in- 

 stance in the SantalacecE, Rubiacece^ Dijpsacecs^ Cuscutece, As' 

 clepiadecB, &c.* 



There is indeed no reason why the nucleus may not be de- 

 veloped without suffering this reflexion of its axis, (as ovulum 

 atropum ex nucleo nudo co7istans,) although I have never yet 

 met with an instance of the kind. 



The formative power concentrates itself in such a manner 

 around this extreme point of vegetation that what subsequently 

 appears as separate lateral organs is here consolidated in the 

 shape of a sheath-like envelope. These leaves inclosing the 

 stalk of the last bud are termed ovular membranes, and are di- 

 stinguished by the total absence of spiroidal vessels, which are 

 proper to the raphe, or that portion of the ovulum which is not 

 divided into nucleus and integument; the presence of these 

 vessels therefore would show that the membrane under exami- 

 nation was only an apparent ovular membrane. Still it some- 

 times happens that at a much later period — after fructification 



* R. Brown includes the ApocynecB also under this head ; but they have 

 a simple integument. In these, as well as in the AsclcpiadecSy it is not 

 the nucleus which becomes developed in the interior after impregna- 

 tion, but the sac of the embryo, which becomes at an early period filled 

 with opaque albumen, which is visible after impregnation as a dark kernel 

 perceptible through the integument. 



