From: Frond architecture of the rootless duckweed Wolffia globosa
 | Wolffia arrhiza | Wolffia columbiana | Wolffia borealis | Wolffia australiana | Wolffia globosa | Wolffia microscopia |
---|---|---|---|---|---|---|
Epidermis | A single epidermal layer with chloroplasts | A single epidermal layer with chloroplasts | A single epidermal layer with chloroplasts | A single epidermal layer with chloroplasts | A single epidermal layer with chloroplasts | The upper single epidermis almost completely lacks chloroplasts |
Stomata | – | – | 40–50 | More than 40 | 314.34 ± 46.99 /mm2 | Two to three rows of stomata in the dorsal surface |
Mesophyll | The upper palisade-like cells subjacent to the lower vacuolated cells | A single mesophyll cell size and type | Vary in size from small cells toward the dorsum to large cells toward ventrum | The upper third was loosely packed palisade-like parenchyma cells, the lower two thirds were composed of large, highly vacuolated cells | Vary in size from small and dense palisade-like parenchyma cells in dorsum to large and empty vacuolated cells in ventrum | Centre composed of loosely arranged parenchymatic cells interspersed with air spaces towards the dorsal side and more tightly packed parenchymatous cells with small air spaces towards the ventral surface |
Chloroplasts | Concentrated in epidermis, mesophyll cells and vaculated cells | Mainly concentrated in epidermis | Concentrated in dorsal mesophyll cells | Concentrated in dorsal mesophyll cells | Both in the mesophyll cells and epidermis | Prominent in the lower epidermis and ventral parenchymatic cell layers |
Transfer cells | – | Present in the epidermis | Absent | – | Present in adjacent mature mesophyll cell | – |
Pseudoroot | Absent | Absent | Absent | Absent | Absent | Present |
Reference | [15] | [17] | [17]; [18] | [16] | Current study | [19] |