Mr. J. Miers on the Biarnoniacese. 161 



*o 



On the other hand, in some few genera, as in Jacaranda, 

 Fridericia, Eccremocarpus, and Calampelis, there is no actual 

 dissepiment, but the placentations are parietal along the middle 

 of two parallel valves, which lines of placentation nearly touch one 

 another, but do not meet in the axis : this linear placentation 

 projects but little above the surface of the valves, and is reflected 

 right and left into narrow plates parallel with the valve, which 

 plates are crenately lobed, each lobe bearing a seed. In Jaca- 

 randa the seeds are arranged parallel to the valves. In Eccre- 

 mocarpus (I speak rather of Calampelis, which has sufficient 

 claim to be generically distinct) the seeds are more imbricately 

 pendent. In Fridericia the structure of the capsule and seeds 

 completely agrees with that of Jacaranda. 



It has been held as a general rule that, throughout the order, 

 the direction of the radicle is centrifugal in regard to the axis 

 of the fruit : this is true in all the Eubignoniea, and in such ge- 

 nera of the CatalpecR as have a simple transverse dissepiment ; 

 but many exceptional cases occur. The instances of Spathodea 

 and Stereospermum have already been mentioned (p. 160), where 

 the radicle is neither centrifugal nor centripetal, but lies in a 

 transverse direction parallel to the diameter of the fruit : a 

 similar direction exists in Sparattosperma and Heterophragma : 

 in Jacaranda it has the same position, while in Calampelis it is 

 almost centrifugal. On the other hand, in Platycarpum and 

 Henriquezia the radicle is decidedly centripetal, as I have shown 

 it to be in certain species of Spathodea. In Oxycladus its dire'c- 

 tion is equally abnormal : here the ovary is bilocular, and the 

 ovules, all heterotropal, are in a divaricating position, placed in 

 collateral pairs down the middle of the dissepiment, with the 

 micropyle directed to the axis. One of the cells becomes abor- 

 tive, and in the other one only a single superior ovule becomes 

 perfected, which occupies the entire space of the cell, and by the 

 pressure of growth thus becomes pendent, so that the radicle is 

 neither centrifugal nor centripetal, but points to the apex of the 

 fruit. 



Having brought together these facts, we are better prepared 

 to inquire into the construction of the carpellary arrangement 

 in the Bignoniacece. We find here, generally, an ovary formed 

 of two cells separated by a complete dissepiment, a simple style, 

 and a stigma consisting of two dilated lamellffi, corresponding 

 most frequently in position with the cells. Upon this prima- 

 facie evidence, the inference would naturally be that the normal 

 number of its carpels must be two ; but when we come to in- 

 quire a little further, we find great difficulty in accounting for 

 the mode of dehiscence of the capsule and the position of the 

 seeds on the dissepiment, upon this hypothesis. We must bear 



