Araliaceae. 



species in question is also uncertain, since drupes ringed above and below the 

 middle can be observed in P. Kavaiensis; the drupes of P. dipyrena are ringed 

 above the middle only. 



KEY TO THE SPECIES. 



Drupe ringed at the base. 



Stigmas 2 to 3, sessile P. gymnocarpa 



Drupe ringed either above or below or at the middle. 



Stigmas 2, 3 to 4, sessile P. dipyrena 



Stigmas 4 to 5 on a conspicuous style P. Kavaiensis 



Pterotropia gymnocarpa Hbd. 

 (Plate 143.) 



PTEROTROPIA GYMNOCARPA Hbd. Fl. Haw. Isl. (1888) 151; Harms in Engl. et Prantl 

 Pflzfam. Ill, 8 (1898) 31. Heptapleurum gymnocarpum Del Cast. 111. Fl. Ins. 

 Mar. Pae. VI (1890) 183. Dipanax gymnocarpa Heller PI. Haw. Isl. (1897) 870. 

 Leaves 3 to 4 dm long, leaflets 9 to 11 (according to Hillebrand 15 to 17), 8 to 18 

 cm long, 4.5 to 8 cm wide, ovate oblong, the lower pair diminishing in size on petioles 

 of 2 to 18 mm, obtuse or obliquely acuminate, with rounded base or unevensided, char- 

 taceous to coriaceous, glabrous underneath, shining above; rhachis of panicle rather 

 short, with 3 to 5 umbellately radiating primary branches of 10 to 20 cm, the flowers 

 about 12 in an umbel at the ends of racemose and umbellate secondary branches of 

 5 to 9 cm, on pedicels of 8 to 20 mm; calyx very short; petals 6, rarely 7, cohering at 

 the apex, about 8 mm in length; ovary 2 to 3 celled (in one of the writer's specimens all 

 ovaries are two celled, one of which is abortive); stigmas sessile; drupe globose (accord- 

 ing to Hillebr.) or oblong-turbinate in the writer's specimens, 12 to 15 mm long, and 

 about 7 mm in diameter, nearly entirely free and naked, the adherent calyx forming a 

 low disk at its base; pyrenae thin papery, ovoid, beaked above and faintly notched below 

 the beak. 



This is a small or medium-sized tree reaching a height of 15 to 30 feet. It 

 differs from the other two species in its smaller leaves and leaflets, which be- 

 come quite glabrous when old, while only the very young branchlets are mealy. 

 The branching habit is similar to Oahuan species of Tetraplasandra, 

 rather than Pterotropia, and it is oiten mistaken for such at first glance. It 

 inhabits the main range of Oahu, to which island it is peculiar. It is, however, 

 easily distinguished from Tetraplasandra by its rather dark foliage. 



Fine trees may be found in the forest on the windward side of Punaluu and 

 above Kaliuwaa valley at an elevation of 2000 feet or more, usually along 

 streambeds and in gulches. It is associated with Pelea sandwicensis, Euphorbia 

 Rockii, Hibiscus Anwttiaitus, Syzijyium sandivicense, Elaeocarpus bifidus, Pit- 

 tosporum, etc. 



On Mt. Olympus at the head of Palolo Valley near the summit ridge fine 

 trees may be observed ; also on Mt. Konahuanui of the same range. The biggest 

 trees occur in the Punaluu Mountains of the Koolau range. Hillebrand 's 

 specimens came from Niu Valley. This tree is in every respect a Pterotropia 

 but in habit, as it does not reach the height of the other two species, which is 

 sometimes 60 to 80 feet. 



The trees from Mt. Olympus have a two-celled ovary, while those from other 

 localities are three-celled. The inflorescence is not drooping, but almost erect 

 above the leaves. 



355 



