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Transverse section of an apple leaf. Note the minor vein (between arrowheads) converging with a large vein. The large vein has BS extensions above and below that reach almost to the epidermal layers and are composed primarily of sclerenchyma cells (asterisks). Arrows indicate the phloem of the minor and large veins. Scale bar = 100 μm. [See online article for color version of this figure.]
