ORCHIDACEM 5 



Raceme ^-Q cm. long, arcuate. Flowers distichous, minute, about 

 2 mm. long. Perianth spreading. Sepals 2 mm. long, the lateral 

 ones oblong-lanceolate, acute, the upper one obtuse. Petals rhom- 

 boid-spathulate, obscurely apiculate, 2 mm. long. Lip minute, con- 

 cave at base, 3-lobed ; the lateral lobes erect by the sides of the 

 column, ovate-falcate, acute, slightly exceeding the acute, round- 

 apiculate, or triangular mid-lobe when the lip is spread out ; apex 

 of mid-lobe scarcely recurved ; calli 3, 2 lateral, 1 central, obtuse, 

 yellowish. Column minute, with a rostellar projection below the 

 clinandrium in front. PoUinia 4. Fruit a globular capsule, 4 mm. 

 long. 



Although the identity of this interesting species was lost sight 

 of for many years, it has turned up frequently in recent col- 

 lections received from the Philippine Islands. It was originally 

 described as a Philydraceous plant by Nees and Meyen. The 

 material which furnished the first description was in fruit only, 

 and therefore insufficient to establish certainty as to the ordinal 

 position of the plant. Bentham and Hooker's Genera Plantarum 

 places it among the doubtful or excluded genera under Cyperacese, 

 while Index Kewensis gives Acoridium tenellum as a synonym 

 of Ceratostylis gracilis. In the Orchid Review 12 : 219 (1904), 

 Mr. R. A. Rolfe says that he has recently studied the type speci- 

 men of Acoridium tenellum, found by Mr. C. B. Clarke among 

 the Cyperacese of the Berlin Herbariimi. Mr. Rolfe recognized 

 the plant to be a species which Naves had referred to Ceratostylis. 

 Later, with additional material, he concluded that Acoridium and 

 Platyclinis are the same. The former genus has priority over the 

 latter, in case of reduction, and therefore Mr. Rolfe renamed 

 some 32 species of Platyclinis (or Dendrochilum in part). Al- 

 though Acoridium is closely allied to Platyclinis, the absence of 

 arms of the column, the very different clinandrium, and the ros- 

 tellar process above the stigma convince me that further investi- 

 gations should be made before the two genera are united. Mr. 

 Rolfe has kindly examined a specimen of the material upon which 

 the above description and the accompanying plate are based. 



