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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[VOL. 10 



sepals of Abolboda. Because of variation in such patterns between the base and 

 apex of a sepal, however, such patterns should be applied with caution. Un- 

 fortunately, no liquid-preserved sepals of Xyris were available for study. The 

 writer suspects that these would show much resemblance to sepals of Abolboda, 

 and would be worth investigating in any case. 



FLORAL VENATION 



The flowers of Abolboda and Orectonthe are alike in a number of features. 

 The flowers of Orectanthe differ in having non-keeled sepals, in lacking 

 staminodia, and in having larger parts which are more richly vascularized at 

 least in some instances (corolla lobes, sepals) than the corresponding portions 

 of Abolboda flowers. The general venation pattern in the two genera is suf- 

 ficiently similar so that variations are considered below after a description of a 

 typical venation pattern in Abolboda. 



Abolboda. 



The flower of A. linearifolia (figs. 67-81) proved convenient material for a 

 study of venation, and does not appear to differ appreciably from other species 

 in these respects. The levels shown offer a series of selected sections from the 

 base of the flower to the top. Because of venation complexities, a series of sections 

 appeared preferable. The broken line in figures 67-69 is merely used to indicate 

 incomplete separation of a sepal from tissue of the inflorescence receptacle at 

 those levels. 



At the lower level indicated (fig. 67) a vascular cylinder can be seen. The 

 bundles of the cylinder have branched, at a level lower than that shown, to 

 supply the approximately five traces present in each sepal. At the next level 

 (fig. 68) sepal traces are in their characteristic positions, a*nd divergence of 

 median corolla bundles is indicated. Only ovary bundles are present on the 

 central area a short distance above this level. Five traces depart to each third 

 of the corolla tube; these thirds correspond to the three corolla lobes at a 

 higher level. This is more evident in figure 69, which shows two of the three 

 staminodia that will be alternate with these thirds of the corolla tube. There is 

 a clearly definable mid vein in each third of the corolla tube (see particularly 

 figure 72). At the level shown in figure 69, as well as in figure 70, the nature 

 of ovary venation is evident. There are three dorsal carpellary traces and three 

 ventral ones, although the latter are fused together at these levels. At the next 

 higher level (fig. 71) separation of the axial portion of the ovary into three 

 placentas, each with a vein (or in some preparations, a pair of veins) is shown. 



Figs. 67-81. Abolboda linearifolia, successive transections of a flower. Sepals are omitted 

 in figures 72-75, and style only is shown in figures 76-81. Fig. 67. Departure of traces tc 

 sepals. Fig. 68. Departure of traces to corolla. Fig. 69. Base of ovary. Fig. 70. Level at 

 which placentas are united; note three staminodes, each opposite a locule of ovary. Fig. 71. 

 Level at which placentas are separate. Fig. 72. Upper end of ovary locules. Fig. 73. Level 

 of ovary crests; note the triangular style base in center, the three staminodes just inside the 

 corolla, and the two style appendages. Fig. 74. Departure of stamen traces; base of anthers; 

 note several traces in each style appendage. Fig. 75. Level of stamen connectives; note 

 cylindrical conformation of bundles in style of appendages. Fig. 76. Departure of style ap- 

 pendages from style. Figs. 77-80. Branching of bundles in upper portions of style. Fig. 81. 

 Stigma. Vascular bundles in all figures represented by circles (or modified shapes). Scale = 

 2 mm in 1 mm divisions. 



