GERANIUM 349 



Among the anatomical characters peculiar to the plants of this 

 family, the following may be mentioned. Schizogenous secretory 

 cavities containing either an amorphous or crystalline brownish-red 

 substance are found in a number of species of Oxalis. Tannin- 

 secreting cells are common in the roots of Geranium. Calcium oxa- 

 late is secreted usually in the form of solitary crystals or rosette 

 aggregates, raphides occurring only in the mucilage cells of Impatiens. 

 In the pericycle there occur either isolated groups of bast fibers or a 

 composite and continuous ring of sclerenchymatous tissues. The 

 tracheae have either simple porous walls or annular and spiral thick- 

 enings. Myrosin cells, which are characteristic of the Cruciferse and 

 have already been described, occur in Tropseolum. 



GERANIUM. Wild or Spotted Cranesbill. The dried rhizome 

 of Geranium maculatum (Fam. Geraniacese), a perennial herb, 

 indigenous to Canada and the eastern and central United States. 

 The rhizome is collected in the late summer or early autumn. 



Description. Horizontal, cylindrical, tuberculate, or irregularly 

 curved, 2.5 to 5 cm. in length, 3 to 10 mm. in diameter; externally 

 dark brown, wrinkled, upper and side portions with numerous buds 

 or circular stem-scars, under surface with numerous root-scars; frac- 

 ture short; internally light brown, bark thin, wood indistinct, pith 

 large; odor slight; taste astringent. 



Inner Structure. Cork consisting of several rows of tangentially 

 elongated cells; cortex of starch-bearing parenchyma and cells con- 

 taining rosette aggregates of calcium oxalate. The stele is somewhat 

 excentric, having a closed ring of cambium, of which the interfascic- 

 ular is especially developed. Fibrovascular bundles are of the coli 

 lateral type and between them occur isolated strands of leptome 

 (several in each ray) which are developed from the interfascicular 

 cambium; pith composed of numerous starch-bearing parenchyma 

 cells and apparently free from calcium oxalate. With the exception 

 of the tracheae there are no lignified tissues. 



Powder. Dark brown; starch grains somewhat ellipsoidal or 

 ovoid, from 0.010 to 0.015 mm. in diameter; rosette aggregates of 

 calcium oxalate, 0.045 to 0.070 mm. in diameter; tracheae annular 

 or scalarif orm ; parenchyma with irregular tannin masses. 



Constituents. Tannin 15 to 25 per cent, which on hydrolysis 

 yields gallic acid; starch, and calcium oxalate. 



Allied Plants. Other species of Geranium contain similar prin- 

 ciples. 



