12-21 leaflet pairs
3-5 mm long; short beak (near top of seed); loose, shiny, inflated covering often preserved in lake sediments; in photo c...
2-3 mm long, round with pronounced ridge and small beak (at top of seed)
2-3 mm long, round with pronounced marginal ridge and small beak (at end of ridge on top of seed)
leaves in whorls of 6-12; each leaf 8-40 mm long, usually forked in 2-8 segements with spiny teeth along margins; stiff, ...
Terete, black, 0.3-0.5 mm long. Spiral markings (striae). Two basal impressions present.
Elliptic, slender, seed coat shiny, up to 3.2 mm long, 1/3 as thick as long, marked with 30-40 longitudinal rows of obscu...
elliptic, slender, seed coat dull, 1.2-3.8 mm long depending on subspecies. Deeply pitted, 20-60 longitudinal pits.
angular 5-10 sided, ~ 0.5 mm long; reticulate pattern of cell wall clearly visible
elliptic-reniform, 1-2 mm long; divided into 4 segments
earlike shape (with covering removed), 2-4 mm long; short beaked; indented along margin and face; coiled embryo
3-5 mm long; short beak (pictured on top of seed); loose, shiny, inflated covering often preserved in lake sediments; in ...
elliptic, seed coat dull, 2.2-4.5 mm long. Pits 3-4 angles, longer than wide, distributed irregularly across seed coat.
ear shaped to reniform, 1-1.5 mm long, shape similar to Potamogeton; short, thin, straight beak sometimes present
earlike shape (with covering removed; covering is ovate in shape), 4-5 mm long; pronounced beak up to 1 mm long; indented...
earlike shape (with covering removed), 4-5 mm long; pronounced beak up to 1 mm long; coiled embryo
subfossil embryo; ear-shaped; small size suggests that embryo is immature; connections to outer covering visible in image...
subfossil fruit; ear-shaped; small size suggests that embryo is immature
elliptic in outline, lenticular in cross section, body ~5 mm long; abundant marginal spines; woody wall
globose, 0.4-0.5 mm in diameter; covered in prickly tubercles (warty bumps) ridges trisecting spore into three parts
earlike shape (with covering removed), 4-5 mm long; very short, blunt beak; indented along margin and face; coiled embryo...
fragile, dark stem; foliar scars alternate, formed from basal remains leaves; leaves acuminate (tapering to a point) tran...
