However, the DID and BER clades together share echinate
pollen grains where the spines are arranged along (or, where absent, as if on) lophae.
Pollen tricolporate or rarely tricolpate, suboblate to prolate, usually of medium to large size (25-100 [micro]m); exine almost psilate, microechinate to echinate
, exine structure with Anthemoid pattern, x=9.
The Oberhautchen cells of the microdermatoglyphic transition zone (MTZ) were imbricate and brachylamellate, with echinate
apical borders characterized by small (1-2 [micro]m long) spike-like denticles (fimbriae) that lacked pores (Figs.
5 mm wide, slender, wiry, dark (blackish) green; velum coverage 10-20%; moderately congested, almost echinate
megaspore ornamentation pattern [Fig.
hieronymii have echinate
ornamentation similar to that
3 [micro]m diameter, proximal hemisphere laevigate, distal hemisphere echinate
, ultrastructure rugulae and granules.
Microspores brown to dark brown en masse, monolete, 27-33 [micro]m long, 20-23 [micro]m wide, elliptic in polar view, proximal face convex and distal face broadly rounded, perispore surface echinate
with longer echinae distally.
Pollen with supratectal spines often has echinate
orbicules (type I)--e.
type resembles that round occasionally in other dryopteroid ferns (e.
Pollen in this family is periporate, with echinate
5 mm long, 1-2 mm wide, subsessile, apices often trilobate; ultimate segments ovate to suborbicular, 2-4 pairs, contiguous, apices roundish, bases subcordate, subsessile, margins entire; veins flee, 2-furcate; sori at the ends of the veinlets, each covered by a slightly enrolled lobule, pauci-sporangiate; sporangia glabrous; spores tetrahedral, shallowly echinate
, 32 per sporangium.
Using the Lellinger and Taylor system, the following patterns are found in Isoetes microspores: aculeate, with bullae (radially symmetrical, low protuberances), no higher than wide, with a broad base and acute apex; cristate, with walls that are narrow, sharp edged, and nonanastomosing; and echinate
, with stelae (radially symmetrical, high protuberances) higher than wide, conical, widest near base.