THE LOWER DICOTYLEDONS. 309 



32O. Little Celandine {Ranunculus ficaria) . This fami- 

 liar plant, easily recognised by its glossy heart-shaped leaves 

 and its bright-yellow star-like flowers, grows chiefly in moist 

 places, whether open or shaded. 



Dig up entire plants and notice that there is no tap-root 

 and that some of the roots are long, thin, and branched, 

 while others are short, thick, swollen, and unbranched. Do 

 the swollen roots contain reserve-food? How do the two 

 kinds of roots differ in function ? Cut across a swollen root 

 and test with iodine solution : is starch present ? Look for 

 young shoots early in February, before the flowers have 

 appeared, and note that above the swollen roots the young 

 shoot has given off a number of ordinary roots ; the latter 

 serve for absorbing water and salts, while the growth of the 

 shoot takes place at the expense of the food stored in the 

 thick (often club-shaped) root-tubers. Note the large mem- 

 branous sheathing scales (how many ?) which protect the 

 young shoot. Try to find earlier stages, with the young 

 shoot still enclosed in its sheathing scales, before the leaves 

 and the slender roots have grown out ; when were the tuberous 

 roots formed ? 



Examine plants in different stages of growth and at 

 different times of the year, keeping some under observation 

 in pots or boxes, and make out as much as possible of their 

 life-history. How do the root-tubers change as the leaves 

 grow larger and the flowers appear? Note that the leaves 

 are stalked, arise from the stem in opposite pairs (as a rule), 

 and that the base of the stalk is broad and sheathing. 



Examine the flowers (February to May), each on a stalk 

 arising in a leaf-axil. In most cases the flower has three 

 green sepals, and usually eight or nine petals. Each petal 

 has a small scale-like nectary at the base of its inner (upper) 

 surface : why is this surface bright yellow and shiny, while 

 the outer (lower) surface of each petal is dull and dark- 

 coloured ? 



What difference is observed if you visit the flowers on 

 fine sunny days and on dull or wet days ? What advantages 

 does the flower gain by closing in bad weather (wet, cold, or 

 overcast) ? In what kind of weather are most insects seen 

 on the wing, visiting flowers ? Note the numerous stamens, 

 which ripen successively towards the centre of the flower, 



