THE INFLORESCENCE 81 



base, on which are attached the perianths and androecia of all the 

 flowers. In Mitchclla (Rubiaceae), fusion similar to that in Lonicera 

 occurs, but the flowers are solitary and belong far apart, morpho- 

 logically, in the axils of leaves on opposite sides of the stem. The erect 

 flowers are fused laterally to the axis above the node at which they are 

 borne and to one another. The fusion extends to the base of the perianth 

 (sometimes to the top of the corolla) and involves the tip of the modier 

 axis; a falsely terminal, double flower is thus formed. The abortive tip 

 of the stem can sometimes be seen on the double ovary between the 

 perianth tubes. Two solitary axillarv flowers become a falsely terminal 

 inflorescence of two flowers. (Similar conditions are seen in Ephedra, 

 a gymnosperm, in which ovules on opposite sides of a cone axis become 

 fused, forming a falsely terminal ovule.) 



Critical study of other inflorescences reduced to a single flower shows 

 their apparent position to be false. The solitary axillarv flower of species 

 of Vicia is a lateral flower of a reduced axillary raceme (Fig. 31). The 

 pistillate flower of Carex, apparently terminal on a spikelet, is a lateral 

 flower, which, in the reduction of the spikelet, has become adnate to 

 the vestigial tip of the spikelet. The axis tip is seen in related genera 

 and, within the genus, in all stages of reduction and fusion with the 

 ovary. 



Fleshiness, associated with fusion in inflorescences, may obscure, in 

 various degrees, form and structure. The entire inflorescence or only 

 parts may be involved in the fleshy transformation; leaflike or platelike 

 structures are formed in this way. Absence of bracts or distortion in 

 their position may increase difficulties of interpretation. In the Urtica- 

 ceae and Moraceae, fleshy inflorescences are common; the "fruit" of the 

 fig tree (Ficus) is a highly specialized fleshy inflorescence. In this 

 genus, the many inflorescence branches ate erect and closely approxi- 

 mated, fleshy, and fused to one another to form a hollow structure 

 which is open distally. The major bracts may enter into the fusion or 

 remain free on the outer surface of the "fruit." The greatly reduced 

 flowers cover the inner surface of the hollow structure. Other genera of 

 the Moraceae and Urticaceae (Dorstcniu, Elatostemon) show phylo- 

 genetic steps in the development of the fig type of inflorescence. 



Fusion, involving all the parts of an inflorescence and associated 

 with fleshiness, is seen in the fruit of the pineapple plant {Ananas), 

 where the inflorescence axis, bracts, and ovaries of all the flowers be- 

 come intimately fused with one another. 



Fusion of sterile branches of the inflorescence, with the development 

 of much woody tissue, and the transformation of bracts into scales or 

 spines form the burrs of such genera as Castanea and Fagus and the 

 acorn cup of Quercus (Fig. 33). 



