32 VASCULAR PLANTS. 



a cup enclosing the disk flowers ; pappus of the 

 disk generally 0; of the ray hyaline, spreading. 

 U- flowers white. 



36. Lagophylla, Nutt. 



Necessaria. Superflua. Kay-flowers 5, cu- 

 neiform, 3-lobed. Involucre of 5 scales, acumi- 

 nate, with scarious margins, each completely 

 enclosing the corresponding ray-akene. Recep- 

 tacle flat, with 5 pale;e between the disk and 

 ray ; pappus 0. 



. flowers yellow, whitish. 



37. Layia, Hook & Am. 



Superflua. Head ao-flowered ; ray-flowers 

 cuneiform, 3-dentate. Involucre 1-seriate, herb- 

 aceous ; scales acuminate, with scarious mar- 

 gins, completely enclosing the ray-akenes. Re- 

 ceptacle flat, with a row of palere between disk 

 and ray, or paleaceous throughout. Ray-akenes 

 linear, attenuate at the base, and with a flat 

 areola at the top ; pappus of the disk various ; 

 of the ray 0. 



0. flowers yellow ; or tipped with white. 



38 Achyrachaena, Schauer. 



Superflua. Ray-flowers short and hidden 

 Involucre 1-seriate ; scales with scarious mar- 

 gins, embracing the akenes of the ray. Recep- 

 tacle flat, naked in the centre, pakeaceous to- 



