CLASS XXI. ORDER Vill. 373 



also frequently found irregular reniform substances, much larger 

 than the anthers, of which they seem to be a disease. The 

 upper part of the spadix withers with the spathe, while the 

 germs grow into a large, compact bunch of shining scarlet 

 berries. 



Every part of the Arum, and especially the root, is violently 

 acrid, and almost caustic. Applied to the tongue, or to any se- 

 creting surface, it produces an effect like Cayenne pepper, but 

 far more powerful, so much so, as to leave a permanent soreness 

 of many hours' continuance. This acrimony is of a volatile 

 nature and disappears upon boiling or drying. It consists of an 

 inflammable substance, volatile at low temperatures, and not 

 combining with water, or alcohol. —May. — Perennial. 



387. CALLA. 

 Calla palustris. L. Northern Calla. 



Leaves heart shaped ; spathe flat ; spadix covered 

 with perfect flowers. 



A handsome aquatic plant. Root as large as the finger, joint- 

 ed, creeping. Leaves on long stalks, smooth, entire, heart 

 shaped, acuminate with an involute point. Scape smooth, a 

 little compressed. Spathe oval, spreading, recurved, clasping at 

 base, ending in a cylindrical or involute point; green on the 

 outside, white within. Spadix oblong-oval, covered with flow- 

 ers which present the appearance of large, crowded, greenish 

 germs, surrounded with white stamens. 



The root is acrid like that of Arum, but the pungency disap- 

 pears in drying. Linnseus says the Laplanders use it for bread. 

 Calla Virginica. Mich. Virginian Calla 



Leaves sagittate-hastate, with obtuse lobes; spathe 

 elongated, incurved. Mich. 

 Syn. Arum Virginicum. L. 



The leaves of this plant may be mistaken at sight for those of 

 Sagittaria, from which they differ in their shorter and more ob- 

 tuse lobes, and the different distribution of their nerves. They 

 are radical, numerous, large and smooth, with semicylindrical 

 petioles. Spathe erect, green, fleshy, cylindrical, acuminate, and 

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