296 MR. A. S. HOENE— A CONTEIBUTIOIV TO 



influenced by tlie sterile ray-florets in both genera. Here, although the reasons given 

 may now be thought unsound, and the differences between the types compared are 

 greater than in the former case, a second reasonable line of descent on the Saxifragacean 

 side may be contemplated. 



The organization of the ovary of Leycesteria is not far removed from that of Pyrus, 

 whilst biseriate ovules are found in Spircea, but the structure of the ovule is not com- 

 patible wdth direct descent on the Kosacean side. Leycesteria perchance originated 

 from an issue of the pro-Hosacean plexus, in wdiich the ovule itself progressed and the 

 biseriate rows, reduced in Fyrus^ were retained. 



Phylogeny op the Cornace.^. — The Cornacea^ of both Harms and Wangerin are 

 polyphyletic, and the family consists chiefly of outlying forms, representatives of stocks 

 that have become obsolete. 



There is no w^arrant from recent discoveries for the recession of Garrya to the vicinage 

 of the orthotropal cohorts. Garrya is more reasonably linked by slender and far distant 

 threads to the Bruniacese and Hamamelidacese. 



Aucuha is probably a scion from pro-Hosacean stock. Here the descending form of 

 ovule found in JPyrus and Prunus has become specialized, and the ovary considerably 



t 



reduced. 



It is curious that, whilst this morphological analysis dissociates Ga^^rya and Aucuha^ 

 the most successful reciprocal effects in cross-grafting have been obtained with these 

 genera. Owing to the kindness of Sir Harry Veitch, the private records of a long series 

 of experiments, records of successes and failures in cross-grafting, have been placed at 

 tlie writer's disposal. Here, whilst the successful grafts are nearly always between 

 genera of the same family, it must be admitted that failures between nearly related 

 genera are numerous. In one case alone a graft succeeded, and that only for a time, in 

 which genera of different families w^ere used — the reciprocal grafting of Ilex Perneyii and 

 JBrixus balearica. But genera from different families were infrequently chosen for 

 experiment. The following reciprocal grafts failed: — Cornus and Aucuha^ GriseUnia 

 and Aucuha, Samhucus and Viburnum, Loroj)etalu7n and JSamamelis , Listylium and 

 Sycopsis, Nyssa and Aucuha, Aralia and Hedet^a. 



Helicingia is difficult to relate. It may be, perhaps, regarded as an epigynous repre- 

 sentative of a parallel line to the Sapindaceae. 



Davidla and Nyssa are isolated forms abutting on the Araliacege, but scions from 

 different progenitors belonging to a pro-Araliacean stock. Here obtains a specialized 



r 



form of the Rosacean ascending ovule ; so that this plexus might extend through issues 

 now extinct into the primitive Bosacejje. 



Alangiacei© still await a keen scrutiny of the ovule, and leave the respective claims 

 of the Cornacese, Combretacese, and Polyosma unsatisfied. Alangium appears to be a 

 reduced analogue of Davidia, possessing the Cornean type of ovule. 



Corokia and GriseUnia are provisionally regarded as outlying forms to Cm^^iius that 

 have had an independent origin. 



