256 PLANT FAMILIES: DICOTYLEDONS. 



the axils of the leaves, and appear in the spring before the 

 leaves. They hang by long pedicels, and the petals are absent. 

 The calyx is bell-shaped, and 4-9-cleft on the margin. The 

 stamens vary also in number in about the same proportion. 

 A section of the flower in fig. 219 shows the arrangement of the 

 parts, the ovary in the centre. The ovary has either one or 

 two Iocules, and two styles. The mature fruit has one locule, 

 and is margined with two winged expansions as shown in the 

 figure. This kind of a seed is a samara. 



Exercise 70. 



413. The elm (TJlmus americana). 



Leaves. — What is the arrangement of the leaves on the shoot? Sketch a 

 leaf showing its attachment to the shoot, and the relation of the stipules ; 

 note how easily the stipules fall away. 



The inflorescence. — Describe the inflorescence ; a single flower ; sketch a 

 single flower in the position in which it stands on the tree. Cut away the 

 floral envelope on one side ; determine the number of stamens ; the number 

 of pistils ; are the pistils single or compound ? Of how many carpels is it 

 composed ? Sketch a flower with the front part of the envelope and the front 

 stamens removed. What part of the floral envelope is present ? What is its 

 character and form ? What are the relations of the sets of the flower to each 

 other ? In time of appearance how do the flowers compare with the leaves ? 



Describe the mature fruit; how many seed are present? What parts of 

 the flower are united in the fruit ? What is the fruit called ? 



Materials. — Spray of leaves and flowers; it maybe necessary to collect 

 them at different times. Leafy shoots should be collected while some of the 

 leaves are still young in order to preserve some with the stipules, and they 

 may be preserved dry and pressed. Fruits collected at the time of maturity 

 may be preserved dry. 



Order Polycarpic^:. 



414. Lesson VII. The crowfoot family (ranunculacese). — 



The marsh-marigold (Caltha palustris) is a member of this 

 family. The leaves are heart-shaped or kidney-shaped, and the 

 edge is crenate. The bright golden-yellow flowers have a 

 single whorl of petal-like envelopes, and according to custom 

 in such cases they are called sepals. The number is not 



