310 THE LOWER DICOTYLEDONS. 



and the numerous carpels, which are not ready for pollination 

 (i.e. the stigmas do not become expanded and sticky) until 

 most of the anthers have opened (what is the advantage in 

 this arrangement?). Examine the carpels carefully, noting 

 the small stigma on each. Sketch (1) an entire flower, open, 

 (2) the same, closed, (3) a sepal, (4) a petal, (5) a stamen, 

 (6) a carpel, (7) a longitudinal section of the flower. 



The flowers are visited by various insects, the pollen being 

 quite accessible and the honey only slightly hidden, so that 

 flies as well as bees and wasps help in pollination. After 

 pollination the flower-stalk curls over while the fruits are 

 ripening. What other changes occur in an old flower, after 

 it has been pollinated, or at least has had its chance of polli- 

 nation ? How do the petals change in colour, and why do 

 they lose their power of closing up ? It might be suggested 

 that the bleaching of the old petals saves the time of intelli- 

 gent insects, e.g. bees, by showing them that the flower is no 

 longer worth visiting. 



You will generally find that plants growing in deeply 

 shaded places in woods or under dense hedges produce 

 few fruits (why?), but to atone for this the plants produce 

 small tuberous bodies (bulbils) in the axils of the leaves. 

 Each bulbil contains starch and has a resting-bud; the 

 bulbils eventually become detached and give rise to new 

 plants. The shoots die down soon after the fruits have 

 ripened, food being stored for the following spring in the 

 tuberous roots and the bulbils. 



321. Buttercups (Fig. 121) belong to the same genus 

 (Ranunculus) as the Little Celandine. They differ from it 

 in having lobed (often deeply divided) leaves, five sepals, and 

 five petals. 



In a Buttercup flower note the five green sepals ; the five 

 petals alternating with these, each with a honey- scale at the 

 base ; the numerous stamens ; the numerous carpels, each 

 having a small thickened or hook-like stigma. Each of 

 these parts is inserted independently on the receptacle, 

 which is merely the expanded knob-like end of the flower- 

 stalk. There is no cohesion i.e. the receptacle-tissue does 

 not grow up and raise the members of a series of flower- 

 leaves on a basal outgrowth (compare sepals and stamens of 



