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MORPHOLOGY OF THE ANGIOSPERMS 



ovule position in related taxa are all necessary where a carpel has only 

 one or two ovules. These ovules may be survivors of the many ovules of 

 either laminar or submarginal clusters. The terms basal, median, distal, 

 suspended are descriptive, rather than morphological. "Basal" should 

 be interpreted as morphologically subbasal. The "basal" ovules of many 

 taxa, such as Ariemonc and Potcntilla, which have abortive ovules (Fig. 

 42N) and traces to lost ovules along the ventral suture above the normal 

 ovule, show that the functioning ovule is the lowest in the ancestral 

 row. (These genera are achene-bearing taxa, with the achene obviously 



Fig. 86. Longitudinal sections of flower of Peperomia showing solitary, "basal" 

 ovule with fomi of ovule trace, hooked, indicating ovule to be lateral, not basal 

 and cauline. A, P. argijreia; B, P. cniapas. ( After Murty. ) 



reduced from a follicle.) That the apparently basal position in achenes 

 is morphologically submarginal is evident in many taxa by the course 

 of the ovular trace, which shows that the apparent basal position has 

 been obtained by differential growth, a downward "migration of the 

 ovule"; the trace descends to the so-called basal position from an 

 originally more distal position (Fig. 86) — Ranunculus, Piper. (Solitary, 

 so-called basal ovules in syncarpous ovaries may show similar evidence 

 of change in position.) OlDJection has been raised that this roundabout 

 course of the ovule trace has no significance, that it is the result of 

 physiological demand, but vascular bundles, developing in relation to 

 function, as in the fleshy tissues of fruits, do not follow circuitous routes. 

 The term basal is perhaps more often applied to the solitary ovule of a 

 syncarpous ovary, where it is considered to be cauline (Fig. 81). These 

 ovules, as shown by anatomy and comparison with the placentation of 



