432 I)K. A. B. EENDLE— SYSTEMATIC 



71. Base of leaf a' subtending two female flowers (see diagram, fig. 72) ; x, intravaginal scale, x 15 



Specimen from Cuba {Wright). 



72. Diagram of arrangement of leaves and flowers in fig. 71. a, b, pair of leaves at a node; a, fertile 



leaf; b, barren leaf; (1), basal flower, al, first leaf on branch in axil of a ; (2), basal flower^ 

 and a", first leaf on lowest branch of the axillary shoot. 



73. Intravaginal scale, x 30. Specimen from Cuba {Wright). 



74. Seed, x 25. Specimen from Pernambuco {Ridley). 



Najas conferta. (Figs. 75 to 77^ 



75. Leaf, x 4. From Brazilian specimen {Neuivied) in Herb. A. Braun. 

 7Q. Seed, x 15. From Cuban specimen in the same collection. 



77. Markings on seed -coat. Much enlarged. 



Najas microdon. (Figs. 78 to 91.) 



78. Leaf -sheath, front %iew. x 10. Specimen from Guadeloupe {Duchassaing) . 



79. Marginal leaf-tooth from same specimen. Much enlarged. 



80. Male flower, x 28. Specimen from Cuba {Wright). 



81. Transverse section of ditto, showing the four anther-cells, x 30. 



82. Very young female flower. Specimen from Mexico (Schaffner). 



83-90. Series showing variation in form and number of stigmas and spine-arms. 

 83 to 87 from a single plant (Mexico, Hahn) . 



83. Three stigmas, one of which bears a spine. 



84. Two perfect stigmas and a third which passes into a spine-arm. 



85. „ ,, „ and a perfect spine-arm. 



86. One simple stigma and a second branching, the branches bearing spines. 



87. Three spine-tipped stigmas. 



88. Two perfect stigmas only. Specimen from Mexico {Mueller) . 



89. Normal flower with decussating pairs of stigmas and spine-arms. X30. Specimen from Guadeloupe 



[Duchassaing) . 



90. Flower with three long stigmas only, x 35. Specimen from Jamaica {Swartz). 



91. Fruit. X 20. Specimen from Mexico {Hahn). 



Najas flexilis. (Figs. 92 to 98.) 



92. Male flower, young, x 30. Irish specimen. 



93. „ spathe removed. „ 



94. „ showing lateral rupture of spathe by elongation of pedicel, and dehiscence of anther. Specimen 



from Washington, D.C. 



95. Pollen-grain. Highly magnified. 



96. Seed, x 8. Specimen from New York {Torrey). 



97. „ „ „ „ Eastern United States (iVw^^ct^Z). 



98. Markings seen through the polished outer layer of seed-coat. Much enlarged. 



Najas punctata. (Figs. 99 to 102.) 



99. Small portion of leaf-margin, showing spine-teeth and hypodermal fibres. 



100. Intravaginal scales. x 20. 



101. Transverse section of anther, showing arrangement of the four cells. 



102. Female flower, showing two stigmas and a spine-arm. x 27. 



