92 NATIVE BRITISH ORCHIDACE^E 



by me in August, 193 1, iii one of the New Forest stations. Central and Southern 

 Europe, from Belgium and Germany southwards, Corsica, Sardinia, Algeria and 

 Asia Minor. 



Spiranthes ^stivalis Rich., M^m. Mus. Paris, iv, 58 (1818). Ophrys 

 SPiRALisy L., Sp. pi. ed. i, p. 946 (1753). O. ^stivalis Lam. (1797). 



Fertilisation. The floral mechanism is the same as in S. autumnalis, but the 

 visiting insect is not yet known. The flowers are scentless by day, becoming shghtly 

 fragrant in the evening, from which it is probable that it is fertflised by moths or 

 other nocturnal insects, probably the former, as linear viscid glands are specially 

 adapted for adhesion to the proboscis of Lepidoptera. 



Note. The prongs of the green fork left behind when the viscidium is removed, 

 as figured by Max Schulze, and recently by Hegi, appear to be too long, these being 

 in reality very short. PI. E, fig. 6, shows the flowers enlarged (3/1). 



3. Spiranthes Romanzoffiana Chamisso 



PI. 16; PL D, figs. I, 2 (p. 94); PL E, fig. 4 (p. 108). Three-ranked Lady's Tresses 

 Irish Lady's Tresses, Hooded Ladies' Tresses (American name) 



Roots 2-6, long, cylindrical, thick. Stem up to 20 cm. or more, erect, pale green, 

 obscurely triangular and sparsely downy above. Leaves linear, nearly erect, long, 

 narrow, tapering, acute, glabrous; uppermost bract-like, short, lanceolate, tapering 

 to a fine point, 3 -nerved, loosely sheatliing the stem. Spike slightly twisted, dense, 

 many-flowered. Flowers large for a Spiranthes, in three ranks curving spirally, 

 white, scented like hawthorn. Bracts lanceolate concave, sheatliing the ovary, 

 gradually tapering, acute, 3 -nerved (sometimes with branched intermediate nerves), 

 the lower (±3 cm.) exceeding the flower, the upper the ovary, the uppermost 

 forming a tuft in early flower. Ovary cylindrical (±1 cm.), very shortly stalked, 

 not twisted, turned to one side, flat in front, convex behind, with tliree cord-like 

 ridges, pale green, glandular-hairy, bent at the tip, so that the flower stands out nearly 

 at right angles. Sepals and petals adherent, their tips free and turned up, side-sepals 

 joined together beneath the lip, sheatliing its base, lanceolate, acuminate, ±12 mm. 

 long, white, greenish at the base with three green nerves, glandular-hairy outside. 

 Petals strap-shaped, linear obtuse, narrow (±2 mm.), 3 -nerved, adherent to sepals. 

 Lip tongue-shaped, trough-like at base (where there are two short nectariferous 

 glands), curving downwards to the broader rounded frilled finely toothed apex, white 

 with green nerves, giving it a greenish tinge, and with minute papHlas below. Column 



