139 



sometimes confluent at the apex. Filaments 1 mm. long and + '5 mm. 

 thick, with the connective produced at the apex. The ovary is flattened in 

 one plane, 4 mm. by 2'5 mm., 8-10-angled according to the number of 

 stamens. The thick circular style is 1 mm. high. 



IDENBURGIA ARFAKENSIS Gibbs, sp. nov. 



Arbuscula, glaberrima, rarauli divaricati, cortice striato cinerascente praediti. 

 Folia opposita, petiolata, ovato-lanceolata, tenuiter caudato-acuminata, basi ?ttenuata, 

 ghnduloso-serrata, membranacea, nervis subtus prominentibus 5-6, rete venulorum 

 conspicuo. Racemus terminalis, foliis duplo brevior. Tepala 4, petaloidea, decus- 

 sato-iinbricata, rotundata, apice obtusa. Stamina 6, antherarum connective baud 

 apiculato. 



Hob. Arfak Mts., Koebre ridge, on open summit, 9000'. Fl. Dec. 

 6003. 



Leaves 11 by 3*3 cm. (including petiole 6 mm. long and acumen 1*5 cm. 

 by 1 mm.), dull brown in colour above with veins barely visible, lighter 

 beneath with dark brown veins, the midrib being produced into the extreme 

 apex of the acumen. Racemes 2 cm. long; pedicels 6 mm. long, the upper 

 ones shorter. Flowers 5 mm. long in bud. Stamens 4 mm. long and 

 I'l mm. broad, with the rim of the anthers +5 mm. broad and filaments red- 

 brown, when dry. Ovary 3 mm. long. Stigma just over 1 mm. high. 



The Triineniacese comprise the two anomalous genera Trimenia and 

 Piptoealyx (I cannot accept Xymalos as showing any affinity with either 

 genus), which have so far been included in Monimiacese, under Tribe II. 

 Trimeniese, though showing little relation to such a systematic position ; 

 indeed Perkins and Gilg (Das Pflanzenreich, iv. 101. 11), the monographers 

 of that order, consider that with a better knowledge of the two genera tbey 

 would probably show themselves as not related to the Monimiacese. Tlie 

 correctness of this point of view is borne out by the discovery of the new 

 genus Ideriburgia, including two species very closely related to both the 

 above genera, but with a syncarpous bilocular ovary. 



A very interesting sequence in development is shown in the floral 

 structure of the three genera. In Idenburgia the flowers are hermaphrodite, 

 whereas both Trimenia (T. weinmannuefolia Seem, from Fiji, for many years 

 the sole representative of the genus) and Piptoealyx were supposed to be 

 dioecious ; T. papuana Ridley, however, recently discovered in Dutch S.W- 

 New Guinea by Kloss, like /. arfakensis, is hermaphrodite. The monotypic 

 Piptoealyx is dioecious. 



The many spirally-arranged perianth segments of Trimenia, graduating 

 from scales to petaloid tepals, are reduced in Piptoealyx to HX biseriate 

 petuloid tepals ; whereas in Idenlmrgia we get four large biseriate petaloid 

 t e p a l s jn each case, however, equally caducous, falling before anthesis, 

 exposing the stamens before these mature. The structure of the stamens 



M 



