PHYSIOLOGY OF THE FLOWER. 



29 



namous stamens. This flower also presents other points of 

 interest. The corolla tube is strengthened by a backward bend 

 just where the weight of an insect produces most strain, and the 

 tube of the calyx is also thickened. Unbidden guests are deterred, 

 not only by the general hairiness of the plant, but also by a weel 

 of hairs in the corolla tube. 



The allied forms thyme and iwod-sage are both proterandrous. 

 The former reminds one of the pink (p. 124), since first the four 

 stamens project from the corolla, two at a time, diverging widely, 

 and then the style grows rapidly, its forked end sticking right out 

 of the flower. Wood-sage takes advantage of the rudimentary upper 

 lip to curve its stamens sharply back after their pollen is shed. 



The two next examples, meadow-sage and orchis, show in a 

 very striking way the reduction in number of stamens that is 

 often associated with elaborate arrangements. 



Meadow-sage (also garden-sage and a large red garden form) pos- 

 sesses only two fertile stamens, and these are modified (cf. p. 97) 

 in a very curious way. The filaments are 5 



short, and the elongated curved connec- 

 tives are loosely swung upon them. The 

 longer upper part of each connective bears 

 a fertile anther lobe, while the shorter 

 lower part is united with its fellow into 

 a curved plate. 1 When undisturbed, the 

 anther lobes are situated under the hood- 

 like upper lip, and the forked stigma 

 projects beyond them, well out of the 

 way of self-pollination. If, now, a bee 

 lands on the lower lip of the corolla and 

 probes the tube for nectar, its head is sure 

 to strike against the curved plate men- 

 tioned. The result is that the anther lobes 

 are swung downwards and forwards so as to 

 deposit pollen on its back. Further, the 

 sage is markedly proterandrous. The 

 stigma of the young flower is placed too 

 high to be touched, but w T hen mature it 

 bends downward and hangs in front of the 

 flower, so that it must be touched before a 

 bee can settle on the lower lip. 



Early purple orchis (fig. 52). The flower 

 has already been partly described (p. 88). 

 flower is occupied by the "column," or top of the pistil with a 



1 Though two fertile stamens are present, they only produce as much pollen 

 as one, for each has but one anther lobe. 



I 



Fie. 52. — Semi-diagrammatic 

 Viewof Early Purple Orchis 

 [original]. i. St. stem ; 

 Br. ' bract ; 8, S, S. sepals ; 

 P, P. upper petals ; L. la- 

 bellum, the streaks are 

 honey-guides, directed to 

 the opening of the spur 

 (shaded black) ; Sp. spur 

 of labellum ; An. bilobed 

 anther dehiscing by slits ; 

 B. rostellum, below which 

 is the broad stigma(dotted) ; 

 (J v. inferior ovary, twisted 

 so that posterior side of 

 flower is below. 2. pollinia, 

 immediately after removal 

 by pushing end of pencil 

 against rostellum; 3. the 

 same a little later. 



The centre of the 



