244 



KNOWLEDGE. 



[N0\-EMBER. 1903. 



splits length-wise, revealing a number of pollen-grains held 

 together in a club-shaped mass by a number of delicate 

 threads. Each of these pollen- masses is continued down- 

 wards in a delicate stalk which terminates iu a sticky pad 

 overhanging the entrance to the honey- tube. The pistil is 

 represented by a sticky flat surface, corresponding to two 

 stigmas, placed a little Iselow the stamen ; the third stigma 

 being modified into a knob of varied shape (the rosteUum), 

 between the anther and the stigmatic surface. This 

 remarkable flower-structuj-e is especially adapted for cross- 

 pollination by insects, self-pollination being practically 

 impossible ; and, furthennore, only a very few chosen 

 insects can reach the honey, or fertilize the plant. We 

 can imitate the visit of a bee, which is one of the favoured 

 agents, by gently inserting into a newly-opened Orchis 

 llower a sharpened lead pencil, and we will understand 

 how this complicated mechani.sm works. The hypothetical 

 bee's head, pushed into the entrance of the flower (as the 

 insect hangs on the convenient landing-stage formed by 

 the labellum), iu order that its proboscis may reach the 



<S:=p^-^~ 



Fict. 2. — Pollen-mass of Orchis, withdrawn by insertion of a pencil 

 into the llower. a, Position when withdrawn, b. Position after 

 exposure to the air. 



honev stored at the end of the long spur, comes in contact 

 with the sticky knobs which temiinate the polleu-masses. 

 One or both attaches itself to our pencil, which di-aws it 

 out of its sheath as we withdraw it. And now rapid and 

 remarkable changes occur. In about half-a-miuute the 

 attaching cement sets hard and firmly fastens the mass to 

 its newlv-found support. At the same time, owing to the 

 unequal contraction of the stem of the pollen-mass, caused 

 bv drying, its axis becomes bent, and it rapidly bends 

 throvio-h a right-angle, so that the bundle of pollen no 

 longer stands upright on the pencil, but points forward. 

 What will happen when our hypothetical bee visits another 

 flower, we cau see. When the bee's head is inserted into 

 the second flower, the pollen which it carries will, owing to 

 the deflection of its stalk, come in contact, not with the 

 corresponding anther, but with the sticky stigmatic 

 surface which lies immediately below : and thus cross- 

 fertilization is effected. Furthermore, only a little of the 

 pollen will adhere to this stigma, and as the bee visits 

 further flowers, the pollen will be widely spread among the 

 various blossoms, the bundle attached to the bee's head 

 becoming smaller and smaller till at length only the 

 flexible stalk remains. The above description will apply 

 to most of our commoner Orchids, though even among the 

 ■British species a considerable range of form is found. In 

 Eiyipogum, Liparis, and Malaxis the flower is not inverted, 

 the labellum being uppermost : but in Malcuns this is 

 caused, curiously enough, not by the ovary being untwisted, 

 but by its being twisted twice as much as usual, the flower- 

 bud making a complete revolution. Thus, in the curious 

 Epipoyuin we find the coloured labellum forming the roof 

 of the flower, the yellowish lanceolate sepals the landing- 

 stage ; the anther and stigmas are placed on the floor, 

 instead of the roof of the tube, the pollen adhering to the 

 imder-side of the visiting insect. In the Bee Orchis 

 {Ophrys aplf era), ugam, the anther-lobes are not embedded, 

 but dangle freely in front of the stigmatic surface, against 

 which they are blown or pushed, this plant being 

 apparently always self-fertilized, in spite of its elaborate 

 strticture and brilliant colour, which point to entomo- 

 philous habits. The Tway-blade (Listera) and Bird's-nest 



Orchis (Neottia) are, as regards their flowers, remarkable 

 in possessing an exceedingly sensitive rostellum, which, 

 on the lightest touch, instantly ejects a drop i)f gummy 

 fluid, which sets hard iu a few seconds, fii-nily securing the 

 pollen-mass to the object — presumably the head of an 

 insect— which caused the disturbance. 



The British Orchids are over forty in number — forty- 

 four according to the London Catalofjue, which includes 

 one or two which are often treated as varieties. Orchis is 

 the largest genus, numbering twelve species ; and with 

 the allied genus Habenaria, constitutes the bulk of the 

 Orchid flora of our meadows. These are all plants with 

 roundish or j)almated tubers, succulent stems and leaves, 

 and spikes of ]>urple, red, pink, greenish or white blossoms, 

 many flelicately fragrant. The Early Purple Orchis 

 (0. mascida), and the Green-winged (0. Morio), th" latter 



S5^ 



Fio. 3.— Flower of Early Purph- Orchis (O 



1, Side view ; 2, front view. Natural size 



la). 



not found in Scotland, appear first, and brighten our 

 spring pastures. Following them comes a rush of meadow 

 Orchids in June — the Spotted (0. waculata). Broad-leave 1 

 (0. latifolia and 0. incani'ita), Fv;ra.midii\ {0. pyramidalis) 

 very rare m Scotland, Butterfly (Hahenaria chloroleuca 



Fig. 4. — Flower of Spotted 

 Orchis (O. maculafa). x 2. 



Fia. 5.— Flower of Butterfly 

 Orchis {Sabenaria chloroleuca). 

 Natural size.' 



and H. bifolia). Sweet-scented {H. conopsea), and the 

 little Frog Orchis ( ff. virifZis), appear in profusion, forming 

 one of the most charming sections of our native wild 

 flowers. The remaining species of these two genera are 

 not so common. The dark little Orchis ustidata is frequent 

 on limestone or chalk in England, but does not extend to 

 Scotland or Ireland. The Lizard Orchis (0. hircina), a, 

 fine plant with a remarkable long curly labellum, is an 

 exceedingly rare plant of the chalk. 0. purpurea, also a 

 comparatively large plant, is almost confined to Kent. 

 0. militaris has a very limited range in Herts, Berks, 

 Oxford and Bucks. 0. simia seems to be confined to 

 Oxford, Berk.s, and Kent. The last three are all chalk 

 plants, and have been much confused. The rarer species 

 of Habenaria are H. aJbida, a plant which loves pastures 

 on the fringe of the mountains, and has a wide distribu- 

 tion, and the rare little H. intacta, or CIose-Howered Orchis 

 {=.Neotinea intacta), growing on limestone pastures in 

 the West of Ireland, and to which we shall refer again 



