Assertion: naiad's leaf | /r/CapableOf | sheathe at the base
Facets:
Source sentences:
text: Leaves are all submersed, opposite to whorled, firm, bright green turning brownish later in the season, linear in outline, .5 to 4 cm (to 1½ inches) long, .4 to 4.5 mm (to 1/6 inch) wide, pointed at the tip, sheathed at the base, and with large, pointed, spine-tipped teeth or lobes around the edges, 8 to 13 teeth per side on larger leaves, and usually a few small prickles along the midrib on the underside.