EE VISION OF THE GENUS NAJAS. 433 



j^ajas arguta. (Figs, 103, 104.) 



103. Leaf. Natural size. 



104. Marginal leaf-tooth. Much enlarged. 



Plate XLI. 



Najas minor. (Figs. 105 to 115.) 



105 to 107. Forms of sheath-leaves : side view. 



105. From a specimen from Berlin, x 10. 



106. From a French specimen, x 8. 



107. From a Portuguese specimen (Welwitsch , no. 410). x 10. 



108. Male flower, x 30. 



109. „ „ with spathe removed. More highly magnified. 



110. „ „ ,, „ „ and perianth slit and drawn back. 



111. Pollen-grains. Highly magnified. 



112. Elongation of pedicel preceding dehiscence of anther, x 30. 



113. Young female flower, x 25. 



114. Seed, x 12. 



115. Fossil seed from pleistocene, West Wittering, Sussex {Reid). x 13. 



Najas Kurziana, (Figs. 116 to 121.) 



116. Leaf-sheath, x 30. 



117. Intravaginal scale, x 50. 



118. Single tooth on leaf-margin. Highly magnified. 



119. Male flower, x 50. 



120. „ „ showing antlier-dehisceuce. x 60. 



121. Seed, x 30. 



Najas gracillima. (Figs. 122 to 125.) 



122. Leaf-sheath and fruit, x 20. 



123. Marginal leaf-tooth. Highly magnified. 



124. Male flower, x 30. 



125. Pollen-grains. Highly magnified. 



Najas Kingii. (Figs. 126 to 131.) 



126. Leaf-sheath and base of blade, x 20. 



127. Intravaginal scale, x 40. 



128. Marginal tooth of blade. Highly magnified, 



129. Female flower, x 40. 



130. Seed, x 12. 



131. Small portion of surface view of testa. Highly magnified. 



Najas lacerata. (Figs. 132 to 138.) 



132. Leaf -sheath and base of blade, x 30. 



133. Intravaginal scale. X 30. 



134. Apex of leaf, x 40. 



