296 The Natural System of Botany. 



THE NATURAL SYSTEM OF BOTANY. 



NUMBER TEN. 



Order, Onagrace-E — The Evening Primrose Tribe. 



This Order contains many American plants, several of which 

 are esteemed for their beauty. A specimen of the common 

 Evening Primrose, (Enothera biennis, which is found in everv 

 sandy field, will present the student with the characters of the 

 order. The number four will be found to prevail in all parts 

 of the flower. The calyx has four sepals joined into a tube 

 which envelopes the ovary. The petals are four, and from 

 within them arise eight stamens, with long anthers slightly 

 attached by the middle to the filaments. The pollen is pecu- 

 liar, the masses being of a triangular shape, and heid together 

 by delicate threads. The ovary is four-sided, and four-celled 

 and the style separates into four stigmas. Besides (Enothera 

 this order contains the genus Epilobium, a species of which 

 E. spicatum, called Willow-herb, is not uncommon in low 

 grounds, and is one of our most showy native plants. Its long 

 racemes of light purple flowers, and its tall, erect figure, make 

 it very conspicuous. Other northern genera are Gawra, Lud- 

 wigia, and Circaea. The beautiful and much cultivated Fuch- 

 sia also belongs here. It is a native of Chili. This differs 

 from all other plants of the order, in bearing a berry, the fruit 

 of the rest being a dry capsule, and the seeds of Epilobium 

 being furnished with a tuft of down. In Cireaea, the petals, 

 sepals, stamens, and seeds are only two. No useful or medici- 

 nal properties are known to belong to these plants. 



The sub-order Halorage*: contains a few insignificant 

 plants of no importance, such as Hippuris, Horse-tail, and 

 Myriophyllum, the Water Milfoil. In these the petals are often 

 wanting, and the stamens sometimes reduced to two. 



