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A TEXTBOOK OF THEORETICAL BOTANY 



Fig. 171 1. — Zizyphiis jujuba. Fruiting shoot. Photograph 

 supplied by courtesy of the Florida Agricultural Experi- 

 ment Station. 



Species of the genus CoUetia occur in South America and are pecuHar 

 in having two buds developed in each axil. The upper forms a thorny 

 cladode while the lower may produce a flower or a branch of unlimited 

 growth. In some species the flattened spiny cladodes bear small deciduous 

 leaves. In such forms the flowers (Fig. 1712) develop on the cladodes, which 

 are produced in opposite pairs. C. cruciata, the Anchor Plant, is a garden 

 shrub. 



Fig. 17 1 2. — CoUetia crncuita. Shoots with 

 spiny cladodes bearing flowers. 



