pinnule

/pin-yool/US // ˈpɪn yul //UK // (ˈpɪnjuːl) //

羽片,羽片状物,羽状体,羽片状结构

Definitions

n.名词 noun

1
- : Zoology. a part or organ resembling a barb of a feather, a fin, or the like.a finlet.
- : Botany. a secondary pinna, one of the pinnately disposed divisions of a bipinnate leaf.
- : a metal plate with a small hole in it, used as a sight in a quadrant.

Each pinnule has its edges so much recurved that the whole forms a sort of pouch, apparently filled with sporangia.
They occur about midway between the central vein of the pinnule and the margin of the leaf.
The sori are in the form of lines which branch out from the lower part of the pinnule in a fan-shaped manner.
The sori are placed on small veins which grow outwards from the midrib of the pinnule.
Sporangia in oblong sori under a reflexed tooth of a pinnule; indusium broad; rachis dark and shining.