. Critical researches on the potamogetons. KUNGL. SV. VET. AKADEMrENS HANDLINGAR. BAND 55. N:0 5. 35. 0 Oq., str OCT, .0? o tween these chief lateral nerves and the border at equal distance from both appear in broad or middle-sized leaves small secondary nerves (vascular bundles), the leaves thus becoming five-nerved (fig. 12, E, n^). These faint nerves, however, can scarcely be perceived with the usual magnifying glass, and the leaves therefore look three- nerved. The space between the primary lateral nerve and the margin presents a light appearance on account of the interjacent marginal lacu
. Critical researches on the potamogetons. KUNGL. SV. VET. AKADEMrENS HANDLINGAR. BAND 55. N:0 5. 35. 0 Oq., str OCT, .0? o tween these chief lateral nerves and the border at equal distance from both appear in broad or middle-sized leaves small secondary nerves (vascular bundles), the leaves thus becoming five-nerved (fig. 12, E, n^). These faint nerves, however, can scarcely be perceived with the usual magnifying glass, and the leaves therefore look three- nerved. The space between the primary lateral nerve and the margin presents a light appearance on account of the interjacent marginal lacunae, see the fig.! Be- tween the midrib and chief lateral nerves in the upper and lower surface, occur sub- epidermally 1—4 bast-bundles (fig. 12, E, str.) and occasionally a subepidermal strand in the very border with another also farther in (fig. 12, E*). Such mecha- nical strands, however, are never te be found between the chief lateral nerve {n^) and the secondary ones {n^), even in the broadest leaves. In the ordinary »3- nerved» leaves of P. pectinatus the primary lateral nerve runs much nearer to the margin and the secondary nerve or bast-bundle (fig. 16, D, str.) almost subepider- mally at a distance of 2—3 cell- A layers from the marginal epidermis, wherefore it cannot be perceived at all by a usual magnifying glass. On close examination these two spe- cies can easily be distinguished from each other by the leaf-structure. On the other hand the leaves exhibit closer anatomical relations to P. subretusus and recurvatus than to P. pectinatus. Another essential characteristic in the anatomy is the above men- tioned short cubic epidermis-cells (fig. 12, D), of great importance especially in studying the hybrids. The epidermis-cells of the peduncle are somewhat more elongated, about three times as long as broad. The epidemis-cells of the stem, on the other hand, are constantly short even in the most streched internodes. Through this anatomical structure the stem obtai
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1910, bookyear1916
