From the website of the Missouri Botanical Garden:
“palaceus,-a,-um (adj.A): palaceous, margin-attached; “attached by the edge to its support, as the blade of a non-peltate leaf to its petiole or of a spade (pala) to its sleeve and handle” (Stearn); “(obsol.) having a foot-stalk, which adheres to the margin of a leaf, as is usually the case” (Lindley). When the edges of an organ especially of a leaf, adhere to their support (Jackson), as when the leaf blade is attached to the petiole along the margin, resulting in a leaf that is “peltate but with the distal portion of the petiole adnate to the blade, the whole shovel-, or spade-like” (Kiger & Porter 2001) [> L. pala,-ae (s.f.I) a spade or shovel]; see peltate.
Elaphoglossum palaceum (Hook. & Grev.) Sledge
NOTE: palatus,-a,-um (adj.A): variant of palaceus used by Diels; see palaceus.
NOTE: there is a slight confusion in the definitions, where the leaf is not peltate, yet it is partially peltate. The ‘usual case,’ according to Lindley, is simply that any stalk attached to, e.g., a leaf margin, such as at its base, such as a petiole, peduncle, pedicel, etc., is palaceous.”