JOURNA OF PROCEEDINGS. 



137 



scale and one branch from that of the leaf; these parts are always pre- 

 formed and distinctly visible even when not developed. The long and 

 stout flower-stalk, P, without any foliaceous organs at its base, bears on 



n ' -m ' . _ J ■ -A 3 ii 1 _:.- I i_J 1 „ (>,„ 



is terminated Dy a Dud exactly nice me one uescriDeu oeroie ; so, nuwevei, 

 that the scale a has a direction opposite to that of/ and g; consequently, 

 b with P and C with r have the same direction as / and g. 



The following diagram will explain the arrangement and the repetition 

 of the different organs : 



Stem. — The long internode, not quite cylindrical, but depressed and 

 somewhat channeled above, is traversed by 6-9 principal air channels or 

 tube=, of unequal size, arranged in a circle, with numerous smaller pe- 

 ripheral and one central one. The nodes are almost solid, but beyond them, 

 in the next internode, the tubes are continued even with their irregularities 

 and peculiarities, adding new ones when the plant becomes stouter. In 

 both axillary productions, the peduncle and the branch, the arrangement 

 of the tubes is reversed. In the full grown plant the internode is com- 

 monly 12-20 inches long and 5-8 or even 9 lines in diameter. I usually 

 find a pair of small tubes above, 2 or 3 pairs of large ones on the sides, 

 and a single middle sized tube below. In the embryo a pair, sometimes 

 more or less confluent, occupies the side of the lowest leaf, an odd one 

 the side of the second leaf, and 4 or sometimes 5 others the intervening 

 spaces. The stem of smallest size has a small pair above, a large pair 

 on the sides, and a middle sized pair below; in larger stems a seventh odd 

 tube appears between the lowest pair, and in full grown ones an upper 

 pair of small ones completes the circle of nine tubes. In the peduncle 

 the same system of tubes is reproduced (not always so regular) in an in- 

 verse order, so that the small pair is found on the anterior side, or on the 

 side opposite its supporting scale. The branch has at first always six 

 tubes, the smallest pair on the lower side opposite to the supporting leaf. 

 This arrangement, however, is usually only visible near the origin of the 

 branch, because the upward tendency of the developing leaf and flower, 

 which in the bud are directed downwards, imparts to the tender, growing 

 shoot a rotation half around its axis, thus righting themselves, and bring- 

 ing, in the anterior part of the internode, the pair of small tubes to the 

 upper side. Where circumstances, such as hardness of soil in very dry 

 seasons, prevent this rotation or twist, the different organs curve from 

 under the branch upwards to the light. As the branch grows, more tubes 

 are added in the succeeding internodes, just as in the parent stem, from 

 which henceforth it does not differ at all, shooting up a flower and a leaf 

 at each repetition of its simple cycle, and gradually overrunning the whole 

 bottom of the pond with their network. 



Thus the plant continues to grow until sometime in August, after the 

 flowering period is passed, it prepares for winter by depositing in the now 



