INTERDUNAL PONDS AND TAMARACK SWAMPS 181 



vertically flattened. When not in leaf the tree may be recog- 

 nized by the rounded leaf buds that are smooth. Swamp holly 

 (Fig. 200) is a shrub with alternate simple leaves which are 

 coarsely toothed but not spiny, as is suggested by the name of 

 holly. The fruits are red berries, as in the familiar Christmas 

 holly, but they are not clustered. They grow thickly, however, 

 on the shrub and persist through the early part of the winter. 

 Spiraea salicifolia (Fig. 201), commonly known as meadow- 

 sweet, is another low shrub with simple alternate leaves that are 



202 



FIGS. 200-202: Fig. 200. Swamp holly, Ilex verticillata; Fig. 201. Meadow- 

 sweet, Spiraea salicifolia; Fig. 202. Steeplebush, S. tomcntosa. 



lance-shaped and sharply toothed. The flowers, which occur 

 in pyramidal clusters, are pink or pinkish white. Spiraea 

 tomentosa (Fig. 202), or steeplebush, is a still more slender shrub, 

 usually unbranched, the stem being covered with silvery hairs. 

 Conical clusters of pink or purplish flowers make it a conspicuous 

 and attractive plant. Clayton's fern, also called the interrupted 

 fern, the cinnamon fern, and the royal fern are closely related 

 species of the genus Osmunda. The royal fern (Fig. 203) has 

 leaves that are two or three ttmes compounded. The spore 

 cases are borne at the tips of the leaves. The interrupted fern 



