140 



is identical in the three genera, though in Jdenlurcjia they are larger and 

 more massive in size and appearance. 



Dr. Rendle kindly examined the pollen, which is tetrahedral in shape, 

 offering no points of interest or comparison. 



The unilocular ovary of Trimenia and Piptocalyx is identical in structure 

 with the bilocular Idenburgia. This organ is somewhat flattened in one 

 plane, showing angulation according to the pressure and number of the 

 inner whorl of stamens, or in /. arfakensis the one whorl of stamens. The 

 peculiar massive, sessile stigma is also identical, but the shape is masked 

 in the first two genera by the outgrowth of papillae. In Trimenia, however, 

 in the younger stages, the lines formed by the pressure of the stamens 

 before the outgrowth of the papilla) show the similarity of structure with 

 that of Idenburgia. 



The anatomical .characters agree with those given in Perkins and Gild's 

 Monograph of the Monimiacese. The wood in all three genera is soft 

 and pithy. In the three species of Trimenia which I have been able to 

 compare with Idenburgia there is absolute conformity. The primary cortex 

 is characterized by stone cells, united in groups, though in I. arfakensis 

 these ?how a more or less continuous ring; balsam cells, with contents 

 soluble in alcohol, are scattered through the bast. The xylem is composed 

 of radial rows of often chambered vessels of considerable size, with 1-4-celled 

 medullary rays, and is succeeded by a large medulla of parenchymatous cells 

 without contents. In /. arfakensis the vessels of the wood are much smaller. 



There is the same agreement in the structure of the leaves so far as 

 Trimenia and Piptocalyx are concerned ; but in Idenburgia we get a 

 difference between the two species, viz., the small alternately disposed 

 coriaceous leaves of 7. novo-guineensis show a very small-celled epidermis 

 without stomata, no hypoderm, then a regular two-layered palisade-tissue, 

 the lower row of much smaller cells, succeeded by a loose-celled spongy 

 parenchyma and a small-celled epidermis, which alone shows stomata. The 

 much larger quasi-membranous leaves of /. arfakensis agree in structure 

 with those of Trimenia and Piptocdlyx, as given in the Monograph and 

 examined by myself, viz., a small-celled epidermis, without stomata, no 

 palisade-tissue or hypoderm, but a very loose-celled mesophyll interspersed 

 with large secretory cells and showing stomata on the lower epidermis only. 

 Balsam, soluble in alcohol, is distributed equally through all the tissues 

 of leaf and stem in I. novo-guineensis , giving the characteristic red colouring 

 which recalled Drimys in the field. 



This genus is named in honour of Mr. A. W. F. Idenburg, lately Governor- 

 General of the Netherlands Indies, to whom I am indebted lor the many 

 facilities which his great courtesy and interest in the scientific scope of the 

 proposed work most generously assured me while in Dutch N.W. New 

 Guinea. 



