71 



libero ; venulse segment! paucae pinnate dispositae inconspicuae. Sort singuli 

 plerumque ad media segmenta, prope pinnae costam dispositi, indusio persistente. 

 Textura coriacea ; lamina superne fusca, inferne griseo-viridis. 



Hal. Arfak Mts., Koebre Mt., 7000-8000', epiphytic in forest. Dec. 

 5627. 



The lower pinnules are slightly deflexed, and the lowest pair are a trifle 

 shorter than the pair above them. The plant differs in every respect from 

 I), viscosa. 



POLYBOTRYA ARFAKENSIS Gepp, Sp. nOV. 



Stipes paleis linearibus brunneis deciduis 0'5 cm. longis vestitus et earum 

 cicatricibus muricatus, 15 cm. longus, atro-purpureus. Frons circa 1 m. longa, 

 40 cm. lata, bipinnata obovato-lanceolata ; rhachis atro-purpurea paleacea muricata 

 (velut stipes) ad apicem haud evoluta, guperne breviter ferrugineo-tomentosa, inferne 

 parum furfuracea, pinnas circa 9 alternas remotas dimorphas (inferiores 6 fertiles, 

 superiores 3 steriles) gerens; pinnae brevi-stipitatae ad apicem abrupte (haud 

 evolutse), steriles circa 30 cm. longse, 13 cm. latae, lanceolatae, fertiles circa 25 cm. 

 longse, 7'5 cm. latae ; rhachis pinnae superne ferrugineo-tomentosa ; pinnulse alternae 

 circa 12-jugatae stipitatae ; pinnulae steriles 6'5 cm. longae, 1'2 cm. latae, oblongo- 

 lanceolatae acuminatae apice serrato, usque ad \ pinnatifidae, lobis (fere 20-jugatis) 

 rotundatis crenulatis, venulis in lobis pinnatae dispositis c. 3-jugatis; pinnulae fertiles 

 3'5 cm. longae, 4-8 mm. latse, lineares usque ad costam pinnatisectae, lobis parvis 

 oblongis sessilibus propter soros copiosos omnino obtectis. Textura subcoriacea. 

 Lamina superne purpureo-brunnea, inferne pallidior glabra. 



Hal. Arfak Mts., S.W. ridge, Angi lakes, 7000', climbing in forest, 

 clasping trunk to top. Dec. 5984. " Fronds 1 in. long, sterile like barren 

 portion of fertile frond ; fertile frond distinct." 



This fern is remarkable for its dimorphous fronds and pinnae and for the 

 arrested growth of its frond-apices. The material consists of one frond, 

 the six lower pinnse of which are fertile, and the three upper are sterile. 

 The apex of the main rhachis has failed to attain its full development, as also 

 have the apices of the secondary rhachises (pinnse both fertile and sterile). 

 Hence, the proper apices are absent. Whether the apical growth has been 

 temporarily interrupted or permanently nrrested, and whether the arrest of 

 growth is due to injury or is of normal occurrence in the life-history of the 

 plant is uncertain. The lower pinnse are shorter than the others. The 

 sterile pinnules are inserted at intervals of about 2 cm., the fertile at about 

 1*5 cm. The fertile pinnules recall those of Osmunda javanica in shape, but 

 not in arrangement. Dimorphism of frond and pinnse occurs in the tropical 

 American P. osmundacea. 



P. arfakensis climbs by means of its rhizome and puts out its fronds at 

 right angles to the axis of the tree up which it climbs, 



