Laubach (4) suggests that the abaxial stamen is a member of an 

 outer cycle while the two lateral are members of the inner cycle 

 of stamens. 



Each anther bears four microsporangia which differ in their 

 relations in the two forms of stamens. The two lateral anthers 

 are alike in appearance (Fig. 3), but the abaxial has its outer 

 sporangia widely separated and its inner, which are much re- 

 duced in size, also pulled somewhat apart. In all cases the 

 sporangia are functional and the pair' in each lateral half of the 

 anther break together in the customary fashion forming the 

 pollen sacs. These do not dehisce, however, until the flower 

 opens except for a slight break on each side of the anther near 

 its upper end (Fig. 4). The pollen output is liberal, and the 

 spores appear to be uniformly well developed. The pollen grains 

 are ovoid and the exine is encrusted mth scale-like thickenings 

 which stain brilliantly in saf ranin. A few flowers were observed 

 to contain giant pollen grains such as Rogers (5) describes in 

 Melilotiis alba. 



The pistil is long and slender (Fig. 1) and shows also a lack 

 of radial symmetry (Fig. 3). The lateral lobes of the slender 

 style are enlarged and the axial face is nearly a plane (Fig. 3). 

 The stigma bears a tuft of finger-like stigmatic hairs. The three 

 stylar canals, which lead to the ovary below, are initially distinct 

 and each is lined with strongly staining glandular cells. With 

 the passage of the pollen tubes the walls between are more or less 

 disintegrated and sometimes the stylar chambers break together 

 while there remains a foam-like structure filling the cavity. The 

 ovary bears 25-35 anatropous ovules attached to the three partial 

 partitions in the ovary. 



Since the maximum elongation of the flower is only two centi- 

 meters and it can open only in the air and further is not fitted 

 to endure wave action, the whole floral mechanism seems poorly 

 fitted to meet the requirements of the habitat. If its insertion 

 is more than an inch below the surface of the water the flower 

 can not open, but, as noted above, functions as a cleistogamous 

 bud. Practically the only conditions favoring the opening of 

 the flowers are found along the margins of quiet water where 

 the level is lowering. Then the stems of the vigorous plants, 

 developed while the water at that point was deeper, come to lie 



51 



