 This structure rapidly descends down the length of the style via tip-directed growth, reaching rates of 1cm/h, whilst carrying two non-motile sperm cells.
<clarity>  This structure rapidly descends down the length of the style via tip-directed growth, reaching rates of 1cm/h, whilst carrying two non-motile sperm cells.
 The pollen tube structure rapidly descends down the length of the style via tip-directed growth, reaching rates of 1cm/h, whilst carrying two non-motile sperm cells.