92 RUELLIA CILIOSA. LONG-TUBED RUELLIA. 



the dye-stuff. Mr. Darwin believes that some of the plants be- 

 longing to the order of Acauthaccce are especially adapted to 

 cross-fertilization. On the other hand, the next-door neighbor 

 of our species, R. strepens, often bears cleistogene flowers, or, in 

 other words, flowers which mature in the unopened bud, and 

 which are, therefore, absolute self-fertilizers. 



The flowers of the Long-tubed Ruellia are very beautiful. 

 They are, however, said to be very fugaceous, each one last- 

 ing only for a day; but if this be correct in all cases, they 

 must be produced daily in great abundance. Our species 

 commences to bloom in June, and continues till September, 

 and there is scarcely a day within this period that the 

 student may not find flowers for examination. The writer of 

 this saw the plant growing in Tennessee in the middle of Au- 

 gust, covering dry and exposed banks with a mass of blossoms, 

 and producing a truly beautiful spectacle, such as could hardly 

 be excelled by any other of the wild flowers of that region. 



The order to which the Ruellia belongs, being chiefly a tropi. 

 cal one, is represented by comparatively but few species in the 

 United States. Our Long-tubed Ruellia is rather circumscribed 

 in its geographical distribution. According to Dr. Gray it is 

 found in " dry soil, Michigan to Illinois and southward"; Prof. 

 Wood locates it in "rich soils. Western and Southern States"; 

 and Dr. Chapman says it grows in " dry soil, Georgia, Savannah, 

 and westward." Its most natural home seems to be west of the 

 AUeghanies ; and it is common in Indiana, Ohio, Michigan, and 

 Nebraska. It passes south through Kansas and Missouri, but 

 has not, to our knowledge, been found in Arkansas or the Indian 

 Territory. 



The specimen from which our drawing was made grew in 

 the Botanic Garden of Harvard University, at Cambridge, Mass. 



Explanation of the Plate. — i. Branchlet and flowers. — 2. Full-face view of a flower. 

 — 3. Half-mature seed-vessel, with the long, slender segments of the calyx. 



