201 



SOME BORNEAN AROIDE^. 



By H. N. Ridley, C.M.G., F.R.S. 



(Plate 527.) 



Aridarum, nov. gen. 

 Planta pusilla herbacea, foliis pluribus linearibus angustis 

 coriaceis enervibus, marginibus et costa incrassatis. Scapus apud 

 folia exortus brevior, gracilis. Spatha parva cylindrica rostrata. 

 Spadix brevior cylindrica. Flores feminei circiter 16 ad basin, 

 pistillis subglobosis, oblongis, stigmatibus discoideis ; ovulis 

 pluribus orthotropis. Flores masculi, stamina oblonga marginibus 

 undulatis apicibus complanatis, canaliculars. Flores steriles 

 duo ad latera staminum adnati ; basi breviter triangulares, apice 

 longo setiformi. 



Aridarum montanum, species unica. Herba parva, radici- 

 bus crassiusculis lanuginosis. Folia plura linearia acuminata basi 

 angustata, coriacea, marginibus et costa incrassata, enervia, 12 cm. 

 longa 4 mm. lata. Scapus gracilis bracteis 6 linearibus acumi- 

 natis papyraceis rufo-brunneis 3 cm. longis 3 mm. latis. Pedun- 

 culus 8 cm. longus. Spatha cylindrica abrupte rostrata 16 mm. 

 longa. Spadix cylindrica obtusa brevior. Flores feminei ad 16, 

 dissiti oblongo-subglobosi, stigmatibus discoideis aurantiacis medio 

 depresso. Flores masculi elongato-oblongi, apice lato margine 

 undulato,? canalicula in medio. Flores steriles basibus triangulari- 

 bus apicibus setiformibus. 



Sarawak, Santubong, C. J. Brooks. 



This very remarkable little plant, of which there is only 

 a single specimen in the collection, is allied to the section 

 ChamcBcladon of Homalomena. It differs generically from this 

 genus in the linear coriaceous leaves, and in the peculiar structure 

 of the male flowers. The stamens are longitudinally oblong, and 

 have a rather deep longitudinal groove in the centre. From the 

 sides of each stamen rises what is presumably a sterile flower, 

 consisting of a minute triangular portion ending in a slender seti- 

 form process, which, in the specimen, lies horizontally over the 

 top of the stamen. These processes are about half as long as the 

 stamen. The base of this body is adnate to the lower part of the 

 stamen. The occurrence of sterile flowers usually club-shaped is 

 not infrequent in Homalomena, but they are almost invariably 

 lateral to or among the female flowers, and never adnate to the 

 male flowers nor of this peculiar shape. The inner face of the 

 spathe and the stamens are sprinkled with small red purple dots 

 apparently glandular. 



The plant is obviously xerophytic, which is very unusual in 

 the section to which it belongs. The mountain Santubong, on 

 which it occurs, is at the apex distinctly xerophytic, and has at 

 some period clearly been an outlying island. It has been visited 

 by Beccari and several other botanists, but no one seems to have 

 obtained this little Aroid previously. 



Journal of Botany. — Vol. 51. [July, 1913.] r 



