Entry of water and subsequent germination of hard seeds of Acacia kempeana occurs after the strophiole lifts and cracks. The ‘opening’ of a strophiole is induced by heat and is effected through the splitting of thin-walled cells lying beneath short palisade cells within the strophiole. Estimated pressure increases of greater than 25 % within the vascular bundle, which passes directly under the thin-walled cells, might influence strophiolar lifting. The vascular bundle between the hilum and the adjacent strophiole is virtually devoid of xylern vessels, thereby preventing water entry through the hilum. However, following the strophiole, the vascular bundle obtains a maximum number of about 35 xylern vessels and is itself enclosed in this region by a noticeable group of over 150 thin-walled cells. Many of these thin-walled cells appear crushed along the route of the vascular bundle through the mesophyll layer to the end opposite the hilum. At the non-hilum end, the vascular bundle almost touches the internal side of the seed coat and thus entry of water would be facilitated through this zone to the internal endosperm and embryo.