438 NAIADACEjE. [Zannichellia. 



Sub-sp. Z. polycau'pa, Nolte ; drupelets often 5-6 subsessile, back cylindric, 

 style \-\ as long, stigma large repanded, filament ^-j in., anther 2-celled. 

 — Var. tenuis 1 sima, Fr. ; very slender. 



6. ZOSTERA, L. GRASSWRACK. 



Grass-like marine plants ; rootstocks matted, creeping. Stem com- 

 pressed. Leaves distichous-, sheathing, long, linear ; stipules adherent to 

 the sheathing leaf-base. Flowers in 2 parallel series of alternating anthers 

 and carpels on one surface of a linear membranous peduncled spadix, which 

 is enclosed in a sheathing leaf-like spathe. Perianth 0. Anthers sessile, 

 ] -celled, dehiscence longitudinal ; pollen of slender tubes. Carpels ovoid, 

 fixed laterally ; style subulate persistent, stigmas 2 capillary exserted from 

 the spathe, deciduous ; ovule pendulous, orthotropous. Utricle dehiscent. 

 Seed ovoid, testa tough ; embryo large, oblong, deeply grooved, cotyle- 

 donary end sigmoid, slender, sunk iu the groove, plumule immersed. — 

 Distrib. Various coasts; species 4. — Etym. fao-r-fip, a riband. 



1. Z. marina, L. ; spathe dilated above the peduncle, its blade long, 

 spadix many-fid. margin entire. 



Muddy and sandy estuaries near low-water mark, N. to Shetland ; Ireland ; 

 Channel Islands; fl. July-Sept. — Rootstock slender, rather fleshy. Leave* 

 1-3 ft., §-§ in. broad, obtuse, bright green, opaque, 1-7-nerved. Spathe, 

 including the leafy portion, 6-10 in., varying in breadth as the foliage does. 

 Spadix 1-3 in. Flowers green, usually in series of 2 anthers (perhaps one 

 2-celled anther) and an ovary. Fruit ^ in. furrowed. — Distrib. Most temp, 

 coasts (Arctic). 



Var. mqri'na proper; leaves 5-J in. broad 3-7-ribbed. — Var. anyustifo'lia , 

 Syme ; leaves \-\ in. broad 1-3-nerved. Orkney, &c. 



2. Z. na'na, Roth ; spathe dilated above the peduncle, its blade short, 

 spadix few-fid., margin with inflexed membranous appendages. 

 Estuaries, rare, from Forfar and Argyll to Sussex and Cornwall ; Dublin Bay ; 



fl. July-Sept. — Similar to Z. mari'na, var. anyustifo'lia, but leaves not more 

 than 6 in. by g-£ broad; fruit shorter and very obscurely striate. — Distrib. 

 Atlantic coast of Europe, N. Africa. 



7. NA IAS, Z. 



Very slender, submerged, fresh-water herbs. Leaves linear, opposite 

 fascicled or whorled ; stipules adnate to the leaf-base. Flowers 1 -sexual, 

 solitary or crowded. — Male. A solitary 1-4-celled anther enclosed in 2 

 sheaths, the outer sheath toothed ; pollen large, globose. — Female. A soli- 

 tary sessile carpel, naked or enclosed in sheaths ; style short, stigmas 2-4 

 persistent subulate ; ovule basal, erect, anatropous. Drupe small ; epi- 

 carp thin, separable. Seed ovoid, testa thin ; embryo straight, oblong, 

 radicular end largest. — Distrib. Various climates ; species 10. — Etym. 

 va'ids, a water-nymph. 



