20 



RACEMOSE INFLORESCENCES 



[CH. 



pendent. The bracts and bracteoles may be caducous, and 

 are not always developed (e.g. Cruciferse) and the length of 

 time during which the peduncle actually grows and gives 

 off lateral pedicels varies much in some Crucifers, for 

 instance, it goes on elongating for several weeks or 

 months. 



The principal characters of the Kaceme are, then, the 

 elongated peduncle, the flowers on lateral pedicels about 

 equal in length, and their development in acropetal or as- 

 cending order. The raceme sometimes terminates at length 

 in a flower e.g. Acer and Berberis, whereas the typical 

 raceme of Prunus Padus, P. Laarocerasus, Red and Black 

 Currants, &c., does not. There is no doubt that in the 

 former case we have transition to the cymose type. 



The following trees and shrubs furnish examples of 

 flowers in racemes : 



Cherry Laurel 

 Sycamore 

 Bird Cherry 

 Portugal Laurel 

 Petty Whin 

 Red Currant 

 Arbutus Unedo 

 Ling 



Loiseleuria 



Menziesia polifolia 



Vaccinium uliginosuin 



Barberry 



Mahonia 



Robinia 



Cowberry 



Laburnum 



Gorse 



Black Currant 

 Bearberry 

 Bell Heather 

 Erica vagans 

 E. carnea 

 E. ciliaris 

 Rhododendron. 



If we suppose a raceme to have the peduncle shortened, 

 and the pedicels of the lower flowers long, and those of 

 the upper ones shorter and shorter as we ascend, so that 

 all the flowers come to open at a common level or nearly 

 so, the flat or slightly convex bunch of flowers is termed 

 a Corymb (Fig. 3, D) ; e.g. Prunus Mahaleb, Pear, Haw- 

 thorn, &c. That the true corymb is merely a shortened-up 

 variety of raceme is shown by the fact that a raceme is 

 frequently a corymb when young, and gradually attains 



