Some Ferns of the Robertson Nature Reserve

THIS WILL BE ONE OF A SERIES OF POSTS ON FERNS IN THE ROBERTSON NATURE RESERVE (over time).

Arthropteris tenella   Rhizome very long-creeping, rigid, to 6 mm diam., densely covered with brown scales. Sori ± circular, indusium absent. 

Arthropteris tenella growing
on Sassafras trunk in
Robertson Nature Reserve.

Click on close-up images to see structural details of structure of the fronds of these ferns, the venation and sporangia.

Some Fern terminology from the PlantNET Glossary:
sporangium: a structure in which spores are formed. pl. sporangia.
sorus: a discrete aggregate of sporangia in ferns. pl. sori
stipe: the petiole of a fern frond.
lamina: an expanded portion of a leaf or petal. pl. laminas.
pinna: a primary segment of the lamina of a compound leaf. pl. pinnae.
pinnule: a leaflet of a bipinnate leaf. pl. pinnules.
rachis: the axis of a pinnate leaf, 
                         or of a pinna in a bipinnate leaf.
petiole: the stalk of a leaf. adj. petiolate. 
alternate: of leaves or flowers, inserted singly at different levels
along the branches
opposite: inserted at the same level, 
(as in, leaves on the opposite side of the stem).  

Arthropteris tenella

Upper view of leaf frond
Arthropteris tenella
Note: each pinnule ("leaflet) is on its own petiole (stem).

Underneath of leaf front.
Spore sori clearly visible
(click to enlarge image)
Arthropteris tenella

Botanical illustration courtesy of PlantNET
Arthropteris tenella
 
NOTE:
Illustration appears to show the pinnae as "opposite"
In fact they are not arranged that way, but are "alternate".

http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Arthropteris~tenella