166 



DlDISCUS ARFAKENSIS Gibbs, sp. HOV. 



Planta perennis ; caules erecti vel decumbentes, glabri, teretes, tenuiter striati, 

 remote foliati. Folia alterna, petiolata, petiolis basi dilatatis, longe setoso- 

 ciliolatis, ad basin quasi 3-5-partita, laxe setoso-pilosa. Scapi in axillas foliorum 

 teretes, nudi. Umbella multiflora, pedicellis glabris, compressis, floribus multo 

 longioribus, involucrum poryphyllurn, foliola lineare-lanceolata, 1-2 dentata. 

 Galycis dentes 5, deltoidei, persistentes. Petala alba, obovata, apice acuta, plus 

 minus inflexa. Fntctus a latere valde compressus, late cordato-rotundatus ; meri- 

 carpia sequalia, glaberrima, 3-vittata. 



Hob. Arfak Mts., on -ridge running up to the Angi lakes, 8000'. Fl., 

 Fr. (yg.). Dec. 5513. 



A plant with spreading radiating branches +3 dm. long. Radical 

 leaves on petiole +4'5 cm. long are 3 cm. long and +4 cm. across, 

 broadly rotundate, 3-partite, each part 2-3-lobed, the lobes further divided 

 into unequal rounded-acute teeth, with white setose hairs in the sinuses and 

 along the veins. The leaves on the branches occur singly at each node, at 

 diminishing intervals, from 10 cm., up the stems, with sparsely setose petioles, 

 the longest being +3-5 cm. ; the laminae are more finely divided than is the 

 case in the radical leaves and are somewhat pentamerous in outline, +5 cm. 

 across and 2*5 cm. long, 3-partite, the two lateral parts being divided again 

 to the midrib, so that they appear 5-partite. Peduncles + 2 cm. long arise 

 singly in the axils of the upper leaves, bearing umbels 1 cm. long by 

 1*5 cm. broad, the involucre equalling or slightly exceeding the pedicels, 

 + 6 mm. long. Flowers 2'5 mm. across. Stamens +1'5 mm. long ; 

 anthers '5 mm. long. Style '5 mm. long. Mericarps immature, 3-ribbed. 



This species belongs to Domin's Calycina group (p. 42) with calyx 

 of rive triangular teeth, and is nearest to D, saniculcefolius (Stapf) Merr., 

 var. bruchystylus Dom., from Mt. Scratchley ; it is more robust in habit and 

 less hirsute, but may prove identical on more material becoming available. 

 Domin considers the Calycina group in Didiscus, which includes the palseo- 

 tropic species, to represent the more ancestral branch of the family ; 

 Pseudocalydna showing atavistic tendencies. To quote Domin, " the 

 presence of the calyx teeth in the endemic species in the Malayan and 

 Papuan provinces, also in the Queensland 2). geraniifolius (Bail.) Dom., 

 must be considered as an older and more ancestral condition." The addition 

 of two more species in these groups to the New Guinea Flora certain! v 

 confirms the correctness of this view. The four species now known from the 

 mountains of Malaya include D. celebicus (Hemsley) Dom., from Bonthain 

 Peak, 10,000', in S. Celebes ; D. sanicula'folius, from Kinabalu, 7000- 

 13,000', Mt. Halcon in the Philippines, 7300', and New Guinea at 10,000', 

 with the above. 



