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irregularly on the ventral side; pollen threadlike. Fertile flower 
fixed on the back near the middle; ovary attenuate into a style as 
long as itself; stigmas 2, capillary. Mature carpels flask-shaped, 
membranaceous, rupturing irregularly, beaked by the persistent 
style. Seeds ribbed, the ribs showing through the dried pericarp, 
enclosed in a firm membranaceous test; embryo thick, ellipsoidal, 
the cotyledonary end contained in a longitudinal furrow. 
Species 5 or 6, natives of temperate seas throughout the world. 
Of these 3 are found on the North American coast. 
1. ZOSTERA MARINA, L. Sp. Pl. 968 (1753). 
Leaves ribbon-like, obtuse at the apex, 1-5 feet or more long 
and 1-4 lines wide, having 3-7 principal nerves and many fine 
ones between them, the nerves often obscure. The sterile plants 
are generally larger and more vigorous than the fertile. Spadix 
34—215 inches long; flowers about 3 lines in length, crowded, 
varying greatly in the proportionate number of each kind, and 
from 10 to 20 of each. Sometimes the anthers are arranged 
obliquely in 2's and 3's. Ovaries somewhat vermiform. At 
anthesis the stigmas are thrust through the opening of the spathe 
and drop off before the anthers on the same spadix open, showing 
that they are fertilized by pollen from other plants. The anthers 
at the time of anthesis work themselves out of the spathe and dis- 
charge the sticky, stringy pollen in the water, thus leaving the 
ovaries by themselves, which then appear regularly disposed in 
two rows. Seeds cylindrical, strongly 20-ribbed, about 1 % lines 
long and % line in diameter, truncate at both ends. The ribs 
show very clearly on the pericarp. 
The plant described under the name Z. Oregana, by Dr. S. 
Watson in Proc. Am. Ac. 26. 131 (1891), was founded upon a 
single specimen in the Gray Herb., collected by Hall in Oregon in 
1871. A careful examination of this shows that it is only our 
common Z. marina. The only substantial points on which Mr. 
Watson relies to establish the species are the long straight beak of 
the fruit and the lack of a foliar appendage on the spathe. The 
beak is characteristic of all Zostera fruit, and the single spathe on 
Hall’s specimen has the appendage broken off, as the jagged edges 
seen under a lens distinctly show. I have seen scores of them in 
