filamentous

The plumes in question consist of long filamentous feathers that grow from the neck of the egret and also from its breast.
A Bird Calendar for Northern India|Douglas Dewar
Ligniform asbestos, or mountain-wood, is a variety presenting an irregular filamentous structure, like wood.
The New Gresham Encyclopedia. Vol. 1 Part 2|Various
Mycelioid: A filamentous colony, with the radiate character of a mould (Fig. 141, c).
The Elements of Bacteriological Technique|John William Henry Eyre
Filamentous: An irregular mass of loosely woven filaments (Fig. 142, a).
The Elements of Bacteriological Technique|John William Henry Eyre

Refraction Strong: Outline and surface of relief strongly defined; dense, not filamentous colonies.
The Elements of Bacteriological Technique|John William Henry Eyre

Origin of filamentous