OPHRYDE^—SERAPIADIN^—ACERAS i6i 



Wliether the absence of a spur is sufficient to justify the separation of Aceras from 

 Ordis is open to doubt. It appears to be the only important point in wliich the two 

 genera differ. That Aceras is very closely allied to Onh's wHitaris, purpurea and 

 Simla is shown by the characteristic odour of coumarin (as in woodruff) common to 

 the leaves of them all when dried, by the resemblance of the helmet to that of these 

 three species, and of the lip to that of O. simia, and by the readiness with wliich hybrids 

 occur with the latter species when they grow together, which shows that they are 

 not infrequently visited by the same insects, 



I. ACERAS ANTHROPOPHORA R. Br. 



PI. 34 A. Man Orchid 



Tubers thick, ovoid or sub-globose; roots several, moderately thick. Stem erect 

 (20-30 cm.), solid, cylindrical, slightly ridged above, pale green, glabrous, with 

 obtuse membranous leafless sheaths at base. Leaves sub-erect or spreading, sheathing 

 at base, oblong or oblong-lanceolate, but little narrowed at the base, 6-12 cm. long 

 by li-^i cm. broad, keeled, more or less acute, glabrous, dark green or grey-green, 

 glossy on both sides, with innumerable wliitish dots beneath, smooth to the touch, 

 of a rather firm consistency, with 3-4 nerves on each side of the mid-rib, usually 

 with a fainter nerve between each pair. Basal leaves close together, the upper erect 

 clasping the stem, with sometimes a narrow membranous acute bract-Uke leaf above. 

 Spike erect, long, narrow, cylindrical. Flowers many, close together except at the 

 base, small, green often edged red, with green, yellow or dull red lip. Bracts half 

 as long as ovary, or less, membranous, i -nerved, tapering, acute. Ovary stalldess, 

 erect, slightly spreading, cylindrical or slightly triangular, ± i cm. long, twisted, 

 glabrous, green with sLx cord-like ridges. Sepals 6-7 mm. long, forming with the 

 petals a short globose or ovoid helmet, adherent for about half their length, free at 

 the tip, ovate to ovate-lanceolate, obtuse or moderately acute, i -nerved, light green 

 edged violet- or brownish red. Petals slightly shorter and much narrower, linear, 

 rather obtuse, greenish, i -nerved, covering the edges of the sepals internally, and 

 making the helmet water-tight. Lip without spur, pendent, narrow, oblong, greenish 

 or yellowish often edged with brownish red, sometimes pure yellow or crimson-red, 

 twice as long as the sepals, shaped like the body of a man, with two linear long very 

 narrow side-lobes and two shorter equally narrow terminal lobes sometimes with a 

 small tooth between. At the base the lip divides into two whitish shining thickened 

 folds (with a narrow V-shaped passage between them) which curve round and join 

 the base of the column, enclosing a shallow cup on the floor of which are two small 

 depressions (visible beneath as httle humps) which, according to Darwin, are the 



