CLASS PENTANDRIA. 
189 
LECTURE XXV. 
CLASS V. PENTANDRIA. 
The class which we are about to examine is said to compre- 
hend more than one tenth part of all known species of plants. 
It differs from the class Syngenesia in having its five stamens 
separate, while the Syngenesious plants have the same number 
of stamens united by means of their anthers. Plants w ith five 
stamens, including those which have anthers united, are said to 
constitute one fourth part of the vegetable kingdom. 
ORDER MONOGYNIA. 
There are six orders in the class Pentandria, the first of which, 
Monogynia, is large and important. Here we find the 41st nat- 
ural order of Linnaeus, the Asperifolice , a name derived from 
two Latin words, asper, rough, and folium, leaf, signifying rough 
leaved plants. These have monopetalous corollas, with five sta- 
mens and five naked seeds. The seeds are dicotyledons ; this 
natural family is found in the 8th class of Jussieu, and by him 
is called boraginece from the genus Borago. “ The change in 
the corolla of these plants, in general, from a bright red to a 
vivid blue as the flower expands, apparently caused by the 
sudden loss of some acid principle, is a very curious phenom- 
enon.”* 
The Cynoglossnm is perhaps as common as any of the aspe- 
rifolue or rough leaved plants. Its common name is hound’s 
tongue, so called from its soft oval leaves, which are thought to 
resemble the tongue of a dog. Although the Cynoglossum is 
classed with the rough leaved plants, its leaves are remarkably 
soft, appearing to the touch like velvet ; it is about two feet 
high, the flowers are of a reddish purple, growing in panicles. 
The Lungwort, ( Pulmonaria,) 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 proper- 
ties ; a species, the arvernis or Forget-me-not, is an interesting 
little blue flower. The Gromwell, (Lithospermum,) is a rough 
* Smith. 
Class Pentandria — How different from the class Syngenesia — Order Mo- 
nogynia — Natural family — Asperifoliac — rough leaved plants, including' 
Hound’s tongue, Lungwort, Gromwell, and Borago. 
