22 CORYMBOID INFLORESCENCES [CH. 



the outermost are longer than the inner, and thus bring 

 all the flowers up to a common level, or slightly rounded, 

 surface (Fig. 5). The true, typical corymb is, as we have 

 seen, simply a somewhat compressed raceme ; but in many 

 cases the corymboid inflorescence is really a Cyme in 

 composition, as we shall see, and should properly be 

 termed a Corymboid Cyme. 



True corymbs are rare, but many of our trees and 

 shrubs have corymboid inflorescences not strictly racemose 

 in origin, as will be shown later. 



The following afford examples of corymbs : 



Pear Norway Maple Apple Maple. 



When the shortening of the primary axis is so pronounced 

 that all the pedicels appear to arise from one point, and 

 spread out like the ribs of an umbrella, the inflorescence 

 is an Umbel (Fig. 3, B), e.g. Ivy (Fig. 6), Cowslip, species 

 oi Allium, Umbellifera', &c. 



The following afford examples of umbellate inflo- 

 rescences : 



Erica Tetralix Cherry Andromeda 



Prunus Avimn Ivy Umbellifera?. 



The umbel of the Cherry, Prunus Avium, &c., is devoid 

 of a terminal flower ; whereas in some umbel-like tufts, 

 e.g. Almond, such a flower exists, whence we have again 

 transitions towards the cymose type. 



In these cases of racemose inflorescences with a 

 shortened primary axis, and where the flowers on the 

 elongated pedicels are brought to a common level or 

 nearly so, it is clear that the outermost flowers correspond 

 to the lowermost in a raceme, and the order of expansion 

 is from outside to centre, and so it came about that such 

 inflorescences of the racemose type are often termed 



