Stipules have abaxial collenchyma but without sclereid ideoblast.
Chiou-Rong Sheue, Ho-Yih Liu, Yuen-Po Yang 2003, 'Morphology on Stipules and Leaves of the Mangrove Genus Kandelia (Rhizophoraceae)',Taiwaniahttp://tai2.ntu.edu.tw/taiwania/abstract.php?type=abstract&id=21. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Older cortex contains more sclereid layers and the time period of their formation extends continuously.
Sławomir Janakowski, Władysław Golinowski 2014, 'Sclerification in the bark tissues of common fir (Abies alba Mill.)', Acta Societatis Botanicorum Poloniaehttps://pbsociety.org.pl/journals/index.php/asbp/article/view/702. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
Later, new sclereid layers are formed successively in nonfunctional secondary phloem and cortex.
Sławomir Janakowski, Władysław Golinowski 2014, 'Sclerification in the bark tissues of common fir (Abies alba Mill.)', Acta Societatis Botanicorum Poloniaehttps://pbsociety.org.pl/journals/index.php/asbp/article/view/702. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
A correlation was found between the number of sclereid layers and the age of the tree.
W. O. Golinowski 2015, 'The anatomical structure of the common fir (Abies alba Mill.) bark. II. Quantitativechanges in bark tissues within the stem', Acta Societatis Botanicorum Poloniaehttps://pbsociety.org.pl/journals/index.php/asbp/article/view/5293. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
The differences concern mainly the structure of the successive sclereid layers and the duration of the process of their filling.
W. O. Golinowski 2015, 'The anatomical structure of the common fir (Abies alba Mill.) bark. II. Quantitativechanges in bark tissues within the stem', Acta Societatis Botanicorum Poloniaehttps://pbsociety.org.pl/journals/index.php/asbp/article/view/5293. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)