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Ruppia.'] cv. NAIAD ACE^. 485 



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which are more or less elongated, sometimes linear-lanceolate, ob- 

 tuse at the base, or decurrent on the foot-stalks. The lower leaves 

 appear to differ from the submerged leaves of all the others, except 

 jP. ohhvQus, in having their substance composed of the same small, 

 but distinct, cells or reticulations as the floating ones. These sub- 

 merged leaves are frequently Avholly wanting, especially when the 

 plant grows in very shidlow water. Chamisso and Schlcchtendal 

 describe the lower petioles as leafless, which, according to them, is 

 the principal difference between this and the last species; but such 

 assuredly is not always the case. 



2. Ruppia Linn. Kuppia. 



Flowers perfect, about 2 on a spike (or spadix?) arising from 

 the sheathing bases of the leaves, which perform the office of a 

 spalha. Perianth 0. Stem. 4. Anthers 1 -celled. Style and 

 stigmas undivided. Achenes 4, on long stalks, 1 -seeded. Al~ 

 himen 0. — N"amed after Henry Bernard Ruppius^ author, in 

 1718, of Flora Jenensis. 



1. R. maritima L. {Sea K). E. B. t. 136. ; FIooL in FL 

 Land. t. 50. — a. Peduncles elongated, leaves broader, sheaths 

 inflated. — /3. Peduncles shorter, leaves narrow, sheaths small 

 close. R. rostellata Koch. 



Salt-water pools and ditches. %. 7, 8. — Stems slender, filiform, 

 flexuose, branched, leafy. Leaves linear, setaceous, with sheaths 

 sometimes narrow and small, at other times large and inflated. Spadix 

 at first very short, mcluded in the sJieath or spatha, with 2 greeu 

 flowers one above another on opposite sides, and quite destitute of 

 perianth. Anther sl-dige, sessile, bursting horizontally, 1 -celled. Mer- 

 tens and Koch say that each pair 'forms the 2 cells of 1 anther; 

 and that there are in reality but 2 sessile stamens. Pollen a tube, with 

 _ S globules, 1 in the middle and 1 at each end of the tube. Germens 

 cl* resembling 4 minute tubercles in the centre between the anthers. At 



the time of flowering, the spadix lengthens remarkably, to the height 

 of 5 or 6 inches or more, and becomes spirally twisted, so as to bring 

 the blossoms to the surface of the water; but Mr. Wilson observes 

 the fruit to be submerged in every stage. When the germens swell, 

 their base is elongated into a footstalk, one or two inches long. Each 

 then becomes an oblique ovate, acuminate, fleshy achene or drupe. 

 This drupe is sometimes more beaked than at other times, and the 

 sheaths of the leaves are occasionally but little dilated : then the plant 

 becomes R. rostellata of Koch and of Reichenbach in his Iconog. 

 1. 174. f. 306, which indeed is the more common state of the plant, 

 with us. In R. maritima the anthers (anther -cells, Koch) are said to 

 be oblong, 11 times longer than broad, in R. rostellata nearly round 

 or subquadrate. It is a very widely diffused plant, being found in 

 America, the Sandwich Islands, and on the coasts of Tranquebar and 

 Ceylon, constantly preserving the same appearance. 



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