512 ORDER ALISMACE2E, OR WATER-PLANTAIN TRIBE. 



that of the deficient stamens, which should be opposite to the 

 petals ; and the fifth and sixth, the rows actually present, the 

 position of which does not properly correspond with that of the 

 outer whorls of the flower.* Now this view of the matter, which 

 may be considered forced and speculative, is very interesting 

 when it is compared with the fact, that the tendency to the pro- 

 duction of one or two additional whorls of stamens, which have 

 been inferred to exist in this instance, is actually manifested in 

 other species of Alisma, one of which has nine, and another 

 twelve stamens. Had the six stamens been in the position 

 represented in the third and fourth lines, there would have been 

 no reason to suppose that any more existed in an undeveloped 

 state, or that the plant was likely to be allied to any with 9 or 

 12 of these organs. The ovaries of the Alisma Plantago consist 

 of about twenty-four (eight times three) carpels, which are quite 

 distinct from each other, every one having its own style and 

 stigma ; they are arranged in a somewhat triangular manner, in 

 three clusters. The number varies in other species, and may be 

 regarded as indefinite. In most instances, there is but one ovule 

 in each cell ; and the fruit consists of a triangular head of dry 

 one-seeded nuts, very much resembling that of the Ranunculacese. 

 From the aquatic species of that order, indeed, in which the 

 veining of the leaves departs from the regular Exogenous cha- 

 racter, and the parts of the flower are arranged in threes, this 

 group is not far distant ; and this is one of the instances which 

 show that even the most positively defined groups are liable to 

 approach one another, through aberrant forms, in which the 

 characteristic peculiarities of each are shaded off, until they 

 almost blend together. 



689. Some Botanists separate from this order the Butomus 

 or Flowering-Rush, and its allies, on account of their many- 

 seeded follicles, to the whole inner surface of which the seeds 

 are attached; this plant receives its scientific name (which 



* This view is given on the authority of Dr. Lindley ; if the idea formerly 

 suggested (. 303), however, should prove well-founded, as to the parts of a 

 verticil being often formed by a single leaf, a much simpler explanation of the 

 double row of stamens may be adopted. 



