290 THE FRUIT. 



dorsal suture, as in Iris, Hibiscus, GEnothera, &c. In this, the 

 dissepiments remain intact. If they break away from the centre 

 then they are borne on the middle of the valves, as in the figures 

 above cited. If they remain coherent in the axis but break away 

 from the valves, the result is one form of what is called 



550. Septifragal dehiscence, i. e., a breaking away of the 

 valves from the septa or partitions, as shown in Fig. 616. This 

 represents the loculicidal form of the septifragal mode, which is 

 less common than that of the accompanying diagram, Fig. 617. 



Here the partitions alternate 

 with the valves ; that is, the 

 dehiscence of the pericarp is 

 of the septicidal order, as 

 near as may be, but the par- 

 titions do not split, wherefore 

 the valves break away at the 

 common junction. To this 

 the term marginicidal has been applied. It occurs in the 2-3- 

 carpellary capsule of Ipomsea (especially in the common Morning 

 Glory) , in the 5-carpellary capsule of the North American species 

 of Bergia ; likewise in the 2-carpellary pod of Cruciferse (Fig. 

 623), with a difference that the placentae from which the valves 

 break away are here parietal and the partition is abnormal. 



551. The terms septicidal and loculicidal apply equally in plan, 

 though not with etymological correctness, to one-celled capsules 

 with either parietal (495) or free central (599) placentae. When 

 the dehiscence is of the septicidal type and the placentation pari- 

 etal, the (half) placentas are borne on the margin of the valves, 

 as in the Gentian family and the species of Hypericum with one- 

 celled capsule. When the placentae are borne on the middle 

 of the valves, as in Violets, the dehiscence is of the loculicidal 

 type. In the case of free central placentas with no trace of 

 partitions, the character of the dehiscence may usually be deter- 

 mined by the position of the styles or stigmas relative to the 

 valves. 



552. Dehiscence may be quite normal although very partial, 

 as when confined to the apex of the capsule of Cerastium and 

 of Primula, and even to the pores under the radiate stigmas 

 of Poppy. 



553. Irregular or abnormal dehiscence is such as has no respect 

 to the normal sutures ; as where the dehiscence is transverse ; 



FIG. 616. Diagram of loculiddally septifragal dehiscence. 617. Same of septicidally 

 or rather marginicidally septifragal debiscence. 



