AND GENERA OF PLANTS. 303 



Obs. — Aster gracilis is a true Aster, nearly allied, indeed, to A. surculo- 

 sus and A. spectahilis. The receptacle is naked, the achenium nearly smooth, 

 with five striae, scarcely, however, compressed; the pappus, pale brown, is sca- 

 brous, but not thickened. The floral rays are long and blue; the involucrum 

 at length somewhat squarrose. 



Heleastrum, (notwithstanding the slight difference of pappus,) ought, I 

 think, to be reunited with Aster. The achenium is quite similar to that of 

 Aster gracilis, to which section, and A. surculosus, it evidently belongs. 



Biotia. We have but two well marked species. Of B. corymhosa I have 

 seen two varieties, which insensibly lose themselves in each other, on an ex- 

 tensive comparison, in nature as well as in the herbarium. The B. commixta 

 is the corymhosa, when grown in dry or rocky situations; in moist grounds the 

 heart-shaped leaves are best developed. The lowest leaves in B. commixta are 

 also cordate. 



The B. glomerata appears to be a species, though it approaches B. commixta. 

 In the herbarium of the Academy of Natural Sciences of Philadelphia it is 

 marked by Mr. Schweinitz under the name qI Aster thyrsoideus, and was ob- 

 tained near Bethlehem, in Pennsylvania. It is distinguished by the shortness 

 of the rays and the brevity of the. pappus. 



GALATELLA. (Cassini.) 



§ *Calianthus. — Liguli in one series, styliferous, elongated; discal florets 

 tubular, five-toothed, hermaphrodite. Receptacle naked, flat, and punc- 

 tate. Involucrum short, imbricated, sepals unequal, herbaceous, narrow 

 and acute, in about three series. Stigmas exserted, clavate, pubescent, in 

 the ray filiform. Achenium obovate, subcylindric, smooth and glandular, 

 with seven to eight strong striae, or ribs; pappus copious, slightly scabrous. — 

 Perennial plants of wet marshes, more or less scabrous; leaves entire, lanceo- 

 late, crowded, glandular punctate; corymb of few flowers, the branchlets 

 almost naked, like peduncles and squamose, the scales gradually passing into 

 those which compose the very regular involucrum. Rays lilac or reddish. — 

 Nearly allied, in habit to Diplopappus linaricef alius, less so to Aster, from 



