354 



STUDIES IN SEEDS AND FRUITS 



a little with their growth and abort as young seeds. When 

 all the ten ovules form mature seeds, or advance considerably 

 in growth, the pod is regular in form and displays no con- 

 strictions ; but more often three or four of the seeds fail in 

 a very early stage, and when contiguous produce a marked 

 constriction in the mature fruit. The club-shaped single- 

 seeded pods, where all the ovules fail except one near the 

 distal end, are very remarkable. 



Reserving my treatment of beaded legumes for a later 

 page, it may be here added that important data relating to this 

 subject are supplied by the legumes of Ulex europaus and 

 Entada polystachya. The examination of the Ulex pods brought 

 out the fact that early abortion of the ovules never even 

 provokes a tendency to moniliform contraction, and that the 

 form of the pod, fixed soon after the fertilisation of the ovary, 

 remains unaffected by the early failure of the ovules. This no 

 doubt results from the structural characters of the pericarp. 



The legumes of Entada polystachya also gave their indica- 

 tions. Here there is no early failure of the ovules after the 

 fertilisation of the ovary ; but all advance considerably in 

 growth, and when failure occurs it is the young seed about a 

 fourth of the normal size that aborts. Here the fruit consists 

 of a series of joints each containing a single seed and held 

 together in the dry state by the " replum," a stout stem-like 

 border that would of itself prevent any constriction of the pod. 

 The usual absence not only of a seed but of any trace of an 

 ovule in the two terminal joints leads one back to an earlier 

 condition of things, when additional ovules existed that are 

 now doubtless only represented by rudiments in the ovary, 

 and disappear altogether in the fruit. 



The behaviour of legumes with one or two seeds is well 

 represented by the fruits of Guilandina bonducella. The ovary 

 here possesses two ovules, and it would seem that as a rule 

 half of the pods mature one seed and the rest two seeds. In 

 the first case the second seed usually attains a diameter of 4 or 

 5 millimetres before aborting, the mature size being about 25 



