Fig. 15.3-7. Tangential section of Zygogynum wood (no common name, in the family Winteraceae). Wood cells sometime give us trouble these ray cells are more or less isodiametric and have thick, lignified secondary walls. That is the definition of a sclereid. But these are not really like the sclereids of pear fruit or coconut shell. They are really like parenchyma cells with thick walls. We often avoid actually giving cells like this a name, and just refer to them as sclerified ray cells.