72 WorsdelL — The Structure and Morphology of the ‘ Ovule ! 
that, as stated above, these same ‘abnormalities’ may be the outcome 
of the working of rigid laws of development whose activity is reproduced 
in other departments of the vegetable kingdom. It is a view which can 
be easily refuted along the lines laid down above. 
Celakovsky regards the ovule as the homologue of a trilobed leaflet 
or segment of the carpel, of which the terminal lobe, involuted towards 
the upper surface to form a cup-shaped structure enclosing the nucellus 
(this latter being an organ of the nature of an emergence or sporangium 
borne on the upper surface of the lobe) is the equivalent of the inner 
integument; while the two lateral lobes, fused by their inner margins 
across the upper surface of the leaflet, represent the outer integument 
(Figs. 5, 6). It is to be noted that, in accordance with what the author 
terms the ‘law of laminar inversion,’ which ordains that two foliar laminae 
fg 
Figs. 5 and 6. Diagrams of a trilobed leaflet showing how, by fusion of the two lateral lobes 
across the upper surface of the terminal lobe through union of the lines fa , ac and gb , be , 
a structure homologous with the virescent ovule is obtained. The nucellus is seen seated as an 
emergence on the terminal lobe of the leaflet (after Celakovsky). fun i funicle. 
are invariably in contact with each other by means of the similar surfaces 
of each, the lower surface of the outer integument contacts the lower 
surface of the inner integument. The above-outlined general position of 
the author derives its entire support from the facts revealed by the so- 
called ‘ monstrosities ’ of ovules where gradual transitional forms between 
the normal ovule and the three-lobed or simple leaflet have been observed. 
In the case of abnormal ovules of the Crucifer, Alliaria , it was the 
inner integument which exhibited the greatest amount of proliferation or 
virescence ; and another remarkable feature consisted in the preponderating 
tendency to proliferation of the funicle rather than of the outer integument. 
So that the ovular leaflet (the virescent ovule) sometimes assumes the form 
