On the geographical distribution of the genus Acrachne

ROXBURGH described in his Flora in the year 1820 a very curious annual grass and placed it in the genus Eleusine as E. verticillata ROXB.. This grass has spikelets which agree in many characters with those of the genus Eleusine, especially as to the rugose grain with a caducous pericarp, but differing from Eleusine in the up to 20-flowered spikelets and in the lemmas with a three-cuspidate summit. The many-flowered spikelets give the plant more the habit of an Eragrostis and under this genus a specimen was mentioned by WALLICH in his Catalogue. There are in the characters of the spikelets many other differences with the genus Eleusine and with Eragrostis. KUNTH and STEUDEL, indeed placed the plant under Leptochloa and there are still other opinions about this plant. An advancement in this matter was the opinion of LINDLEY, who published in the year 1836 a new genus Acrachne WIGHT et ARN., in the second edition of his ”Natural System of Botany“, p. 381, based upon ROXBURGH’s Eleusine verticillata, The name Acrachne was already given by WIGHT et ARNOTT as Acrachne eleusinoides, a nomen in WIGHT, Cat. no. 1760. This name was placed by STEUDEL in the year 1854 under E. verticillata ROXB., a name also accepted by NEES. The name Acrachne, although based upon a species which was validly published, was, however, not described by LINDLEY and the combination A. verticillata was not made by LINDLEY. At that time the genus Acrachne was therefore not valid.