322 MORPHOLOGY. 



the flowt-r of trill iuin sometimes presents. In llg. 3S1 is a sketch 

 of a floNN'er of tri Ilium, made from a photograph. One set of 

 the stamens has expanded into petal-like organs, with the anther 

 sacs on the margin. In fig. 3S0 is shown a plant of Tnllimii 

 grandiflorum in which the pistil has separated into three distinct 

 and expanded leaf-like structures, all green except portions of 

 the margin. 



Dentaria. 



646. General appearance. — For another study we may take 

 a plant which belongs to another di\'ision of the higher plants, 

 the common "pepper root," or " toothwort " (Dentaria 

 diphylla) as it is sometimes called. This plant occurs in moist 

 woods chiring the month of May, and is well distributed in the 

 northeastern United States. A plant is sho«'n in fig. 383. It 

 has a creeping underground rliizome, whitish in color, fleshy, 

 and with a few scales, h^ach spring the annual flower-bearing 

 stem rises from one of the buds of the rhi/ome, and after the 

 ripening of the seeds, dies down. 



'i'he leaves are situated a little abo\'e the middle point of the 

 stem. They are oi)j)Osite and the numlter is two, each one 

 being chvideti into three dentate lobes, making \\'hat is called a 

 comijound leaf 



647. Parts of the flower. — The llowers are several, and they 

 are borne on ijuite long stalks (pedit'els) scattered over the ter- 

 minal portion of the stem. AA'e should now exannne the parts 

 of the flower beginning with the calyx. This we can see, look- 

 ing at the under side of some of the lloucrs, ])0ssesses four scale- 

 hke sepals, which easilv tall awa)' atler the opening of the llower. 

 They do not resemble lea\es so much as the sepals of trillium, 

 but they belong to the leaf series, and there are two i)airs in the 

 set of four. The i orolla also |iosscsscs four petals, which are more 

 expanded than the sc]ials and are whitish in col(.)r. The sta- 

 mens are six in nunflier, one pair lower than the others, and also 



