Typical mesomorphic bifacial leaf of a grass

Bulliform cells collapse & enable folding of lamina

Homogenous mesophyll, large intercellular spaces, moderate sclerenchyma

C₃ photosynthesis

Section through midrib of a leaf of bluegrass (Poa pratensis), a C₃ plant that is mesophytic. Characteristic of leaves in mesophytic grasses is a homogeneous mesophyll of isodiametric loosely arranged cells, and a moderate amount of sclerenchyma. Note the presence of bulliform (motor) cells that are somewhat collapsed, enabling the leaf blade to fold. When swollen by increased water volume in their central vacuoles, the motor cells will extend the leaf lamina to a more open position.

1 = adaxial epidermis, 2 = bulliform (motor) cell, 3 = stoma, 4 = metaxylem vessel in midrib vascular bundle, 5 = phloem of midrib vascular bundle, 6 = abaxial sclerenchyma of midrib, 7 = major vein, 8 = intercellular cavity, 9 = minor vein, 10 = homogenous mesophyll, 11 = abaxial epidermis