Ill] CATKIN: SPADIX, ETC. 25 



found with numerous transitional forms in the Urticacese 

 (Fig. 7, B). 



The true capitulum is even rarer than the umbel and 

 corymb in our trees and shrubs, but the Planes afford 

 examples of inflorescences very like capitula. 



Returning now to the typical raceme. If we suppose 

 the flowers to become sessile on the peduncle by the 

 suppression of the pedicels, everything else being as in the 

 type, the inflorescence is a Spike (Fig. 3, C) ; e.g. Plantago, 

 Mullein, Verbena officinalis, and many Orchids, &c., where 

 the spike is erect, while in other cases it may be pendent. 



Typical spikes are not uncommon, but on our trees and 

 shrubs the spicate inflorescence is far more apt to occur in 

 one of the modified forms to be referred to shortly, 

 especially the Catkin. The best example of the spike 

 among the trees, &c., here concerned, is furnished by the 

 Tamarisk, but the following exhibit inflorescences which 

 are spicate in form, though found to be more complex on 

 dissection, because each bract carries in its axil more than 

 one flower, or something in addition to the flowers : 



Chestnut Alder ? Oaks ? 



Birch Hornbeam $ Empetrum. 



If the spike, erect or pendulous, bears male ^denoted 

 by the sign or female denoted by the sign $ 

 flowers only, with prominent and scaly bracts, it is termed 

 a Catkin ; e.g. Poplar, Willow, &c. (Fig. 8). 



If the axis of the spike is swollen and fleshy, while 

 the base is enveloped in a large sheathing bract (Spathe), 

 it is termed a Spadix, e.g. Arum, Calla and other Aroidese. 

 The apical portion of the spadix is often devoid of flowers 

 and peculiar in shape and hue, and the spathe may be 

 brilliantly coloured (e.g. Anthurium) or white (e.g. Ri- 

 chardia). 



