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their length, terminated by one blue flower, which appears in August 

 and September. 



In the tenth species the stems are five feet high, slender, angular, 

 smooth, but not branching much; the leaves alternate, not very 

 rough; the flowers terminal, solitary, small, and white; the peduncles 

 have very small subulate leaflets scattered over them. 



The eleventh has the stems slender, three feet high, with slender 

 side branches most of their length, so as to form a thick bush; they 

 are terminated by single flowers. 



The twelfth species has the stems upright, two feet high, full of 

 branches, which are filiform ; the stem-leaves being narrow-lance- 

 olate; on the branches linear: the peduncles filiform, striated, one- 

 flowered, with very narrow leaflets on them; the flowers small, with 

 an erect, imbricate, loose calyx; the ray copious, and white; the 

 disk yellow, with fewer flowers. 



The thirteenth species rises four feet high ; the flowers are pale 

 blue, appearing about Michaelmas. The whole plant is tomentose, 

 especially the leaves and calyxes. The raceme simple, with very 

 short peduncles. It is a native of Virginia. 



The fifteenth species has the stem obscurely furrowed, of a pale 

 red, not very erect, but irregularly flexuose, corymbosely branched, 

 the branches divaricate and much divided; the leaves of the same 

 form, sometimes having a single serrature, the edge scabrous, if the 

 finger be drawn toward the base, the surface rough with invisible 

 hairs; the flowers rather solitary, somewhat small, on long, scaly, 

 yellow peduncles; scales of the calyx distant, in five rows; disk of 

 the corolla yellow; ray pale blue, revolute; the height near four 

 feet, having broad leaves at the bottom, which diminish gradually to 

 the top. The flowers appear at the latter end of August. It is a 

 native of Virginia. 



The sixteenth rises to the height of four feet, the stems putting 

 out side branches towards the top, which grow erect, forming a loose 

 spike of large blue flowers, expanding about the end of October. It 

 is a native of North America. 



The seventeenth species has the stems three feet high, with side 



