Complex sentence: At their tips, leaf blades are acute to acuminate (tapering to a sharp point), while at their base, they are either cordate to abruptly contracted and obtuse or long, slender and wedge shaped.
Split into simpler sentences: At their tips, leaf blades are acute to acuminate, meaning they taper to a sharp point. But at their base, leaf blades are either cordate to abruptly contracted and obtuse or long, slender and wedge shaped.