Hmmm, rather a broad sweeping statement to say that pondweed has no external beauty!
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| Potamogeton transverse section through stem |
The image above is another one I took from a prepared microscope slide, again, the colouration is due to stains used to make tissues more obvious. The air spaces which keep the plant buoyant are clearly visible. Buoyancy is necessary to keep the leaves near the surface so that photosynthesis can be maximised. The dark structure in the middle is the vascular tissue, this central arrangement gives the stem more flexibility in moving water. In non woody land plants the vascular tissue is often arranged near the edge of the stem to form a strengthening cylinder; in contrast, root vascular tissue is arranged centrally, thus providing more strength against pulling forces.
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