646 



SCALE-LEAVES, FOLIAGE-LEAVES, FLORAL-LEAVES. 



stand-point the perianth-leaves are, as it were, only antherless stamens, and this view 

 is supported by the fact that in the so-called double flowers the anther-bearing 

 stamens regularly change into antherless perianth-leaves. In the flowers of water- 

 lilies as a rule no sharp limit can be drawn between stamens and perianth-leaves, 

 but a gradual transition from one to the other may be plainly noted. The flowers 

 of certain limes (Tilia Americana, alba, argentea), as well as those of the arrow- 

 grass (Triglochin), of which an illustration is given below, are very instructive in 

 this respect. In the Silver Lime (Tilia argentea, figs. 151 ^ and 151 ') a whorl of 



Fig. 151. — Flowers of the Silver Lime {Tilia argentea), ami of a species of Arrow-grasa {Triglockin Barellieri). 



1 Inflorescence of the Silver Lime, natural size. 2 Longitudinal section tlirongh a single flower. ^ Flower of the Arrow-grass, 

 in the first stage of blossoming. * xhe same flower in a later stage of development ; one of the upper perianth-leaves cut 

 away. -, 3, and ■* are enlarged. 



stamens with anthers is first formed below the pistil, followed by a whorl of leaves 

 without anthers, which, however, secrete honey to allure insects; then again comes 

 a whorl of leaves with, and below these again two whorls of leaves ■ndthout 

 anthers. The same is the case in Triglochin, whose flowera look as if they were 

 composed of two stories standing one above the other, ijuite similarlj^ arranged (see 

 figs. 151 ^ and 151 *). The flower commences below with a whorl of three hollowed 

 antherless leaves; above these comes a whorl of thx-ee leaves with anthers, and the 

 large anthers are surrounded and protected during development by the hoUowed 

 leaves a.s if by a hood; then again follows a whorl of three hollowed antherless 

 leaves, and above these yet again a whorl of three stamens with large anthers, an 



