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 1 and 151 2 ) a whorl of 



Fig. 151. Flowers of the Silver Lime (Tilia argentea), and of a species of Arrow-grass (Triglochin BareUieri). 



i Inflorescence of the Silver Lime, natural size. 2 Longitudinal section through a single flower. 3 Flower of the Arrow-grass, 

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

 away, a, s, 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 without 



o 



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

 composed of two stories standing one above the other, quite similarly arranged (see 

 figs. 151 3 and 151 4 ). The flower commences below with a whorl of three hollowed 

 antherless leaves; above these comes a whorl of three leaves with anthers, and the 

 large anthers are surrounded and protected during development by the hollowed 

 leaves as 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 



