Practice question

Pollen morphology provides key synapomorphy distinguishing major clades: basal angiosperms and monocots produce monosulcate grains bearing single distal sulcus groove, while eudicots comprising majority of dicots about 175,000 species produce tricolpate or derived triporate grains possessing three apertures, grooves, pores or colporate combinations equatorially placed enabling harmonic folding harmomegathy and rapid tube emergence. This tricolpate condition originated about 125 million years ago marking major radiation documented palynologically in Cretaceous sediments. One groove characterizes monocots, two grooves eumagnoliid rarity, no grooves inaperturate condition evolved few taxa, but three remains diagnostic eudicot.