They divide into three to four pinnae which subdivide into many pinnules. Its leaves are bipinnate with linear-oblong and glabrous pinnules. Each of these is further subdivided into branchlets (the pinnules). The arms are edged by feathery appendages known as pinnules. Both arms and pinnules have tube feet along the margins of the ambulacral grooves. The sori are marginal on the pinnules. These have feathery pinnules and are spread wide to gather planktonic particles from the water. The individual pinnules were closely spaced and frequently overlapping. The remaining two herbaceous sections being distinguished by their pinnules, opposing ("Dahlia") or alternating ("Entemophyllon"). Reproduction occurs when some of the pinnules burst, releasing gametes into the water column. The fossil record includes stems, pinnules, and spores. It catches plankton and suspended particles of detritus with the tube feet on the pinnules. The pinnules are attached by a very narrow base. The tips of the pinnules are often more brightly colored than the arms and centrodorsal. Not all the pinnules are reproductive, just those closest to the crown.