ME. G. BENTHAM ON OECniDE-E. 293 



further investigation of its pollen, which our specimens do not 

 enable us to carry out. 



To the above eight genera already recognized as Pleurothalleae, I 

 would add two somewhat anomalous ones — 1. Arpophyllum, a Mex- 

 ican and Central- American genus recently found also in Jamaica, 

 comprising two or three closely allied species or varieties differing 

 from the rest of the subtribe in their large size and long dense 

 cylindrical flower-raceme. 2. Meiracyllium, Reichb. f., a little 

 Mexican plant with small broad sessile leaves on very short sterna 

 at the nodes of the creeping rhizome, and bearing at their base 

 a one- or two-flowered peduncle, entirely as in several species 

 of Pleurothallis ; but the pollinary apparatus is more that of 

 Eriese, and the rostellum is elongated and recurved over the 

 column, in a manner very different from that of any other 

 Orchidea hitherto observed. 



Subtribe 2. Miceostxle^;. — The genus Malaxis of Swartz 

 comprised a considerable number of terrestrial or bog-plants, 

 with small flowers, chiefly from the temperate or subtropical 

 regions of the northern hemisphere. Louis Claude Richard, per- 

 ceiving that it included two very distinct groups, and considering 

 the European, and especially Scandinavian, M. paludosa as the 

 typical species of Swartz's genus, established the other group as 

 a separate genus under the name of Liparis. Nuttall, apparently 

 unaware of Richard's observations, and unacquainted with the 

 M. paludosa, which is not American, regarded the Liparis-group 

 as the true Malaxis, and proposed to separate the other one 

 under the generic name of Microstylis. Lindley retained both 

 Richard's and Nuttall's genera as distinct from Malaxis, which he 

 limited to the single M. paludosa. Darwin has since shown the 

 very close connexion of Microstylis with that species, which 

 Nuttall indeed would probably have included in Microstylis if he 

 had been acquainted with it. It appears, however, to have suffi- 

 cient peculiarities to justify us in following Lindley and main- 

 taining it asamonotypic genus, which with Microstylis (including 

 Dienia) I should place in a subtribe separated from Liparidese by 

 the very remarkable position of the anther first distinctly explained 

 by Darwin. Instead of being incumbent over or inclined towards 

 the rostellum and falling off at or after the discharge of the 

 pollen, as in the great mass of Epidendrese, it is thrown back with 

 the cells turned upwards, and, in most species at least, the anther- 

 case either shrivels up or remains long persistent after the removal 



