84 DIVERGENCE OF VARIATION [ch. ix 



(Ovule erect) 



Flower hermaphrodite. 



Fruit with no hard layer in wall. 



Ovule ultimately pendulous ; perianth 



leaves spurred. Myosurus 



Ovule always erect; perianth leaves 

 not spurred: 

 With honey-leaves. Oxygraphis 



Without honev-leaves. Trautvetteria 



Fruit with hard layer in wall. Ranunculus 



Flower dioecious. Hamadryas 



While almost all of the new and smaller (younger, according to 

 age and area) genera that have to be added to the key that we 

 obtained from the large (old) genera are added simply in such a 

 way that they cluster around some of the big genera, like those 

 just given cluster around Ranunculus, one finds every now and 

 then one or more genera (usually clustered) which do not so 

 obviously represent satellites of the big genera, but have a focal 

 point of their own. Thus among the intermediate genera in 

 Ranunculaceae there appears Paeonia, whose characters require 

 a splitting of the early character of distinction given above and 

 marked A. Instead of leading directly to Aquilegia, Delphinium, 

 and Aconitum, as at present, A has now to include Paeonia, which 

 cannot be easily split off, as was Ranunculus, by extension of the 

 generic end of the key, but has to be split off as follows : 



A: Follicle, etc. 



Outer integument of ovule longer than inner; Paeonia 



no honev-leaves; ovarv wall fleshv. 

 Outer integument not longer, sometimes one Aquilegia, etc., 



integument only; honey-leaves or not; as before 



ovary wall rarely fleshy. 



Passing yet further down the scale of genus-size, Paeonia 

 becomes accompanied by Glaucidium, with two species in the 

 mountains of Japan and China (a much smaller distribution than 

 that of Paeonia, as one would expect upon age and area). As 

 the separation of Paeonia was so comparatively high up in the 

 scale, this small group of two genera is evidently of somewhat 

 different rank from that which surrounds Ranunculus, and is 

 often regarded as a sub-family; but it is important to notice that 

 it is hardly of the rank of the other two sub-families. As a key 

 to the three sub-families, we have 



