5 I 2 NAIADACE/E 



leaves and unbranched peduncle, with 3^-5 whorls, each of 3 — 5 

 rather large, delicate, white or pinkish flowers, rising a few inches 

 out of the water. — Rivers and ditches ; not uncommon. — Fl. 

 July--Sei")tember. Perennial. 



*.S'. heterophylla, a North American species, with ovate unbarbed 

 leaves on long shealliing ])etioles and short peduncles with small 

 white flowers, resembling those of the Water-Plantain.s, occurs in 

 the E.\e. 



3. Damasonium (Star-fruit, Thrumwo-rt). — Aquatic plants with 

 the habit of the Water-Plantains ; but ^^;ith floating leai'es and (') — ■ 

 10 carpels united at their base and spreading horizontally in the 

 form of a star. (Name of uncertain origin.) 



I. D. Alisiiia (Common Star-fruit).— iThe only British species; 

 leaves long-stalked, cordate-oblong, 3 — *5-ribbed, floating ; flowers 

 in I — 3 whorls, stalked, white, ^ in. across, with a yellow spot at 

 the base of each petal ; fruit generally of 6 rather large, 2-seeded. 

 long-beaked, dehiscent carp-Is. Dravetly ponds and ditches in 

 the south; rare. — Fl. June, July. I'ere'nnial. 



4. BuTOMUS (Flowering Rush), repre&nted only by one species, 

 B. unibelldtus, is a tall aquatic with a creeping rhizome; sword- 

 shaped, radical leaves 2 — 4 feet long ; and numerous handsome, 

 rose-coloured floivers, i in. across, in a terminal, bracteate, 

 simple umbel, on a cylindric peduncle 2 — 3 feet high ; the 

 periantJi-leaves are all petaloid ; stameiis 9, with red anthers ; 

 carpels 6, united at the base, many-seeded, dehiscent down one 

 side. — Stagnant water and slow rivers ; not uncommon. (Name 

 front the Greek hous, an ox, and leinno, I cut ; because cattle 

 were apt to cut their mouths with the leaves of some plant to 

 which the name was originally applied.)- -Fl. June, July. 

 Perennial. 



Ord. PXXXVIII. NAiAnAcK.TC. ^Pond-weed FAariLV 



A small Order of aquatic and marsh ])lants, usually with a 

 creeping rlnzome : slender, branched, jointed stems ; leaves 

 sheathing at the base, often floating, sometimes almost leathery, 

 but more frequently thin and |>ellucid ; flowers small, inconspicu- 

 ous, olive-green, snmctimcs solitar\', but more frequently in spikes ; 

 perianth of 3 — d inferior, \-al\-atc scalfcs, tubular, or absent ; 

 stamens i — 6, hypogynous ; carpels i — 6, i-ovuled, indehiscent, 

 sometimes in distinct flowers from the stamens. 



I. Trici.ochix. Leaves linear ; Jtok'crs ebracteate, perfect ; 

 perianth of d similar, erect, green lea\es ;. stamens G ; carpels 3 — 6. 



