EMPETRACEJE. 213 



OBDEB XCI. EMPETRA'CE^E. (CROWBERRY FAMILY). 



Low shrubby evergreens, resembling heaths as to leaves 

 and general aspect. Flowers dioecious or polygamous 

 Calyx somewhat petal-like or none. Ovary 3-9-celled, 

 berry-like in fruit. 



Synopsis of the Genera. 



1. Em'petrum. Flowers scattered and solitary In the axils. Sepals 3, 



somewhat petal-like. 



2. Core'ma. Flowers in terminal heads. Calyx none. 



1. IvU PKTIM H, Tourn. CROWBERRY. 



E. ni'grum, L. (BLACK CROWBERRY.) A slender procum- 

 bent shrub with the foliage and aspect of a heath. Flowers 

 polygamous, inconspicuous in the axils of the leaves. Calyx 

 3 petal-like sepals. Corolla wanting. Stamens 3. Fruit a 

 blackberry-like drupe. Atl. Prov. and northward. 



2. CORE'MA, Don. BROOM-CROWBERRY. 



C. Conrad' ii, Torr. (BROOM-CROWBERRY.) Closely resem- 

 bling the preceding. Flowers dioecious or polygamous, col- 

 lected in terminal heads, each in the axil of a scaly bract, 

 having no true calyx, but with 5 or 6 thin, dry bractlets 

 under each. Stamens 3 or 4 with slender filaments. Drupes 

 small, juiceless when ripe. Atl. Prov. 



ORDER XCII. CERATOPHYLLA'CEjE. (HORNWORT F.) 

 Represented, with us, by a single species. 



CERATOPHYL'LUM, L. HORNWORT. 



C. demer'SUm, L. An aquatic herb, with whorled finely 

 dissected leaves, and minute axillary sessile monoecious 

 flowers, without calyx or corolla, but with an 8-12-cleft 

 involucre. Staminate flowers of 12-24 stamens with large 

 sessile anthers. Pistillate flowers of a single 1-celled ovary, 

 forming an achene, beaked with the slender style. Embryo 

 with 4 cotyledons. Under water in ponds and slow streams. 



