1514 CXXVII. OECHIDEiB. 



Order CXXVII. ORCHIDEiE. 



Flowers hermaphrodite. Perianth superior, irregular or rarely regular, of 6 

 petal-like or green segments, all free or variously united ; 3 outer ones called 

 ^■sepals all similar and erect or spreading, or the dorsal one (next to the main axis 

 unless the flower is reversed by a twist of the ovary) more concave or otherwise 

 -different from the 2 lateral ones (lower ones unless the flower is reversed), which 

 .are always similar to each other ; 2 inner segments called petals, similar to each 

 ■other, one on each side of the dorsal sepal, and sometimes connivent or connate 

 "within it into a (/aZ«rt, sometimes similar to the lateral sepals, or different from 

 •all the sepals ; the sixth segment or third petal called the labellum, different from 

 .all the others (except in Thelymitra and Apostasia), inserted between the lateral 

 ■sepals at the base of the column, and exceedingly varied in size, shape, lobes, 

 calli, fringe, or other appendages. In the centre of the flower or somewhat under 

 the dorsal sepal i.s the column, consisting of the comibined androecium and pistil ; 

 at the apex attached to the dorsal margin is usually one anther, erect incumbent 

 on or adnate to the apex of the column or to the back of the stigma, with 2 cells 

 on its inner face or almost marginal. In the genus Gypripedium which is not 

 Australian, and in Apostasia, there are two lateral perfect anthers. Pollen either 

 -waxy granvilar or mealy, usually more or less distinctly collected into 1, 2, or 4 

 pairs of pollen masses, either oblong or tapering to the upper end, free or 

 .attached by their narrow end, either directly or by a linear or filiform caudicle, to 

 .-a gland on the rostellum or apex of the stigma, or sessile on that apex without a 

 ■gland. In front of the column either at or near its apex or lower down is a 

 concave or rarely convex viscid stigma, the upper margin often produced into an 

 •erect appendage called the rostellum sometimes very short, sometimes as long as 

 or longer than the anther ; each side of the column towards the front shows a 

 I'ono-itudinal angle, often expanded in the whole or part of its length into a wing, 

 ■sometimes continued behind the anther into a hood over it, or expanded into two 

 ;auriclGS or appendages (sometimes described as stamiriodia) one on each side 

 ■between the stigma and the anther, sometimes continued into a basal projection 

 of the column or even continuous with raised lines on the labellum, or in 

 Thelymitra the two wings shortly joined in front of the column, or in Apostasia, 

 the style normally cylindrical with a terminal stigma. Ovary inferior, 1-celled or 

 with ii parietal placentae, or in Apostasia perfectly 3-celled with innumerable 

 ■ovules. Fruit capsular, opening in 3 valves or longitudinal slits, or very rarely 

 succulent and indehiscent. Seeds minute, fusiform or rarely winged, resembling 

 fine sawdast. Embryo a solid, apparently homogeneous body. — Herbs usually 

 perennial, either terrestrial with underground rhizomes creeping or producing 

 annually renewed tubers or thick clustered fibres, or epiphytical with 

 -creeping rhizomes and (often fleshy) fibrous roots adhering to the sur- 

 face of rocks or trunks or branches of trees. Leaves either alternate and 

 -sheathing at the base and sometimes distichous, on flowering stems which when 

 ■epiphytical are sometimes thickened into pseudo-hidhs, or in radical tufts at the 

 base of the flowering stems or in tufts or on pseudo-bulbs distinct from the 

 flowering ones, entire or very rarely lobed (see Acianthus). Flowering stems 

 scapes or peduncles annually renewed, either proceeding directly from the 

 rhizomes or axillary on perennial leafy stems or pseudo-bulbs, bearing usually 

 ■one or more scarious or membranous sheathing scales, either without any leaves, 

 or when leafy 1 or 2 sheathing scales below the leaves and often 1 or more above 

 them. Flowers either solitary and terminal or 2 or more in a terminal raceme 

 or spike, either simple or branching into a panicle, each flower sessile or more 

 frequently pedicellate within a bract, but without bracteoles on the pedicel. 



The Order is one of the most natural and sharply defined, as well as the most numerous 

 amongst Monocotyledons and abundantly distributed over the -whole globe, rare only in some 

 •high Alpine or extreme Arctic and Antarctic regions, 



