176 ORDER SEGREGATA. 



with a gigantic race of plants, the Silphhms, somewhat 

 resembling Sunflowers, but whose generic character is 

 too remarkable to allow them to be mistaken for any 

 thing else. They have a peculiar calyx, with spread- 

 ing or squarrose segments, which are broad, and end 

 in short leafy appendages. The receptacle is provid- 

 ed with chaffy leaflets. The seed is flat, obcordate 

 for inversely heart-shaped), emarginate, and bidentate 

 (or 2-toothed). The flowers are always yellow, and 

 the rays have remarkably long and obvious styles. 

 The infertile discal florets often fall out before the 

 disappearance of the rays. 



The Polymnias, of this order, as well as the pre- 

 ceding, an exclusive American genus, are also gigan- 

 tic yellow flowered plants, growing in rich, moist, 

 shady, and mostly rocky woods. In these the calyx 

 is double ; the exterior being 4 or 5 leaved ; the in- 

 terior 10-leaved ; the leaflets concave by the swelling 

 of the large seed ; the receptacle chaffy ; the seed 

 without pappus. 



In salt marshes is frequently to be found a shrub- 

 by plant with opposite, ovate, lanceolate, deeply ser- 

 rated, and somewhat scabrous leaves ; having depres- 

 sed globular flowers of a greenish color, and without 

 beauty, which will be found to agree with the genus 

 Iva, having a 5-leaved, or 5-parted calyx. The flo- 

 rets of the ray 5 (and small) ; the receptacle hairy ; 

 and the seed obovate, and naked. 



SEGREGATA. 



In this order there are 2 sets of calyces ; the outer, 

 or common involucrum, for such by analogy it really 

 is in the whole class ; and here an inner, or included 

 calyx also of the same character, containing one or 

 more florets, and thus producing, as it were, a doubly 

 compound flower' 



