45 



so, such as those of the Poppy, in which there are 4 petals and 

 2 sepals. The fact is only here emphasized that this is the case 

 in a very large number of plants and the fact will often be 

 found useful in helping us to readily diagnose flowers in the field. 



If now we look at a flower of Berberis Lycium we find, 

 outside the 6 stamens, 12 perianth leaves, the inner 6 of which 

 are all the same size and colour and at first sight appear to be in 

 one whorl with a stamen in front of each of them. The outer 6 

 perianth leaves, however, are distinctly arranged in two whorls, 

 each of 3 leaves, the outer 3 being greenish and sepal-like 

 alternating with the 3 inner leaves which are larger, brighter 

 yellow, and obviously more like petals. If we examine the 

 flower more carefully and remember that as a rule the number 

 of sepals and petals is equal, we find that it is really quite 

 normal with 2 whorls each of 3 sepals, 2 whorls each of 3 

 petals and 2 whorls each of 3 stamens, the members of each 

 whorl alternating with those of the next. In this case the 

 outermost 3 leaves are more or less obviously sepal-like, 

 but the 3 leaves in the next whorl are undoubtedly more like 

 typical petals, and this indicates that the only real difference 

 between sepals and petals is one of position, the former being 

 the outer and the latter the inner set. Outside the outer whorl 

 of sepals there are usually also 2 or 3 small bracteoles which 

 closely resemble the outer sepals, and we see that, so far as mere 

 appearance goes, it is not always possible to readily distinguish 

 bracteoles from sepals. A flower which has its parts in whorls 

 of 2, 3, 4, 5, or 6 respectively is said to be di-, tri-, tetra-, 

 penta- or hexa- merous. 



According as the number of stamens in a flower is one, two, 

 three, or many, it is said to be mon-, di-, tri-, or poly- 

 androus. 



41. A flower which contains Distribution 



both stamens and pistil, or pistils, is said to be hermaphrodite, 

 or bisexual ; a flower which either has no stamens, or no pistil, 

 is unisexual ; a unisexual flower with stamens is a male, or 

 staminate, flower, and is usually shortly written thus $ flower, 

 while one with pistils only is a female, or pistillate, flower and 

 is written ? flower. When the flowers of a plant are unisexual 

 but both $ and s flowers occur on the same individual plant, the 

 flowers are monoecious and the plant itself may be described as 

 moncecious. When the flowers of a plant are unisexual and the <? 

 and ? are found on different individuals the flowers and plant 

 are said to be dioecious. When the flowers of a plant are both 

 unisexual and hermaphrodite, which may, or may not, occur 



