Class XXI. Order VIII. 



Order IV. TETRJNDRM. Four stamens. 



%5%. URTICA. Barren flowers, calyx four leav- 

 ed ; corolla none ; nectary central, cup shaped. 

 Fertile flowers, calyx two leaved ; corolla none ; 

 seed one, superior, shining. 



S53. ALNUS. Barren flowers, ament composed 

 of wedge shaped, three flowered receptacles ; co- 

 rolla four parted. Fertile flowers, scales of the, 

 ament two flowered ; corolla none ; styles two ; 

 seed compressed, ovate. 



Order V. PEJYTANDRM. 



25tt. XANTHIUM. Barren flowers, calyx com- 

 mon, imbricate ; florets funnel form, live cleft ; re- 

 ceptacle chaffy. Fertile flowers, calyx tw r o leaved, 

 two flowered ; corolla none ; drupe dry, prickly, 

 cloven ; nucleus two celled. 



255. AMBROSIA. Barren flowers, calyx com- 

 mon, one leafed ; florets fun nel form, three cleft ; 

 receptacle naked. Fertile flow r ers, calyx one leaf- 

 ed, one flowered ; corolla none ; nut toothed, one 

 seeded. 



256. AMARANTHUS. Barren flowers, calyx 

 three leaved ; corolla none ; stamens three or five. 

 Fertile flowers, calyx three leaved ; corolla none ; 

 styles three ; capsules one celled, opening trans- 

 versely ; seed one. 



Order VIII. POLYANDRLL Eight or mure sta- 



mens. 



%57. SAGITTARIA. Calyx three leaved : co 



