446 



CLASS PENTANDRIA 



LECTURE XXV. 



CLASS V. — PENTANDRIA. 



Fig. 127. The class which we are about to exam- 



ine is said to comprehend moie than one 

 tenth part of all known species of plants. 

 It differs from the class Syngenesia in hav- 

 ing its Jive stamens separate^ while the Syn- 

 genesious plants have the same number of 

 stamens united by means of their anthers. 

 Plants with five stamens, including those 

 which have anthers united, are said to con- 

 stitute one fourth part of the vegetable king- 

 dom. 



Order Monogynia. 

 Asperi/olicB, or Boraginecc. 



Here we find a group of plants called by 

 Linneeus Asperifolice, a name derived from 

 two Latin words, asper, rough, and folium, 

 leaf, signifying rough-leaved plants. These have monopetalous 

 corollas, with five stamens and five naked seeds. The seeds are 

 dicotyledons. Jussieu forms these into the order Borag-inecB, from a 

 genus called Borago. " The change in the corolla of these plants, in 

 general from a bright red to a vivid blue as the flower expands, ap- 

 parently caused by the sudden loss of some acid principle, is a very 

 curious phenomenon."* 



The Cynoglossuvi is, perhaps, as common as any of the asperi- 

 folicB^i or rough-leaved plants. Its common name is hound's-tongue, 

 so called from its soft oval leaves. Although the Cynoglossum is 

 classed with the rough-leaved plants, its pubescence gives to its 

 leaves a softness appearing to the touch like velvet ; it is about two 

 feet high, the flowers are of a reddish purple, growing in panicles.f 

 The Lungwort, (Pidmonaria.) which also belongs to this natural 

 family, has two species in North America with smooth leaves. The 

 Mouse-ear {Myosotis) is valued for its medicinal properties ; a spe- 

 cies, the arvensis, or Forget-me-not, is an interesting little blue 

 flower. The Gromwell (Lithospermum) is a rough plant with white 

 flowers ; the bark of the plant contains so much silex or flinty mat- 

 ter, as to injure the sickles of the reapers, when it grows in the field 

 with the grain. The name, Lithospermum, is from the Greek, lithos, 

 a stone, and sperma, a seed, in allusion to the hardness of the seeds. 

 The Borago is an exotic very common in our gardens. The co- 

 rolla is wheel-shaped, of a beautiful blue colour, having its throat 

 closed with five small protuberances ; the stamens are attached to 

 the tube of the corolla. You must take off the corolla carefully, 

 and you will see the little scales which choked up the throat of the 

 corolla, and the manner in which the five stamens adhere to it. 



lyurida, or Solanece. 



We next meet with a family of plants, named by Linnaeus, Lurida>, 

 Oom their pale or livid colour. Jussieu called them the Solanete, 



* Smith. 



t It is said that the leaves of this plant, if strewed about apartments infested with 

 rata and mice, will expel these vermm. 



Class Pentandria— How different from the class Syngenesia — What are the char- 

 acteristics of the family AsperifoliiE?— Cynoglossum — Lungwort — Myosotis — What 

 other rough-leaved plants are mentioned in the first ordier of the fifth class 7— What is 

 said of the LuridEe or Solaneas 1 



