PLANT ORGANS AND ORGANISMS 211 



Multiple Fruits. The Syconium is a multiple fruit consisting of a 

 succulent hollow torus enclosed within which are akene-like bodies, 

 products of many flowers. Example: Fig. 104 (i). 



The Sorosis is represented by the Mulberry, Osage Orange, etc., 

 the grains of which are not the ovaries of a single flower, as in the 

 Blackberry, but belong to as many separate flowers. In the Pine- 

 apple all the parts are blended into a fleshy, juicy, seedless mass, and 

 the plant is prop agated by cuttings. 



The Strobile or Cone is a scaly, multiple fruit consisting of a 

 scale-bearing axis, each scale enclosing one or more seeds. The 

 name is applied to the fruit of the Hop, Fig. 104 (2), and also to 

 the fruit of the Conifers in which the naked seeds are borne on 

 the upper surface of the woody scales. 



A Galbalus is a more or less globular multiple fruit formed of 

 fleshy connate scales, as in Juniper, Fig. 104 (3). 



Histology of a Capsule, Vanilla. The Vanilla fruit is a one-celled 

 capsule formed by the union of three carpellary leaves and dehiscing 

 by two unequal longitudinal valves. 



Microscopic Appearance of a Transverse Section. Passing from 

 periphery toward the center, the following structures present 

 themselves : 



1. Epicarp, consisting of epidermis and hypodermis. The epider- 

 mis consists of a layer of thick-walled epidermal cells whose outer 

 walls show the presence of a thin yellow cuticle. Stomata are pres- 

 ent in this tissue. The epidermal cells contain protoplasm and 

 brownish bodies. Some also contain small prisms of calcium oxalate 

 and a few, vanillin crystals. The hypodermis is composed of one to 

 several layers of collenchymatic cells with dark-colored contents. 

 Its cells are somewhat larger than those of th e epidermis and thicker- 

 walled. 



2. Mesocarp, a broad region of somewhat loosely arranged large, 

 thin- walled parenchyma cells becoming smaller in the inner zone of 

 this region. Most of these cells contain brownish contents but some 

 possess long raphides of calcium oxalate. If the section be mounted 

 in phloroglucin solution (5 per cent.) and a drop of strong sulphuric 

 acid is added, a carmine-red color will be observed showing the pres- 

 ence of vanillin in this region. Several closed collateral bundles will 

 be seen coursing through the mesocarp. 



