242 HALORAGE.^:. Myr:ophyllum. 



pinnately cut into numerous fine segments. Flowers sessile in the axils of the upper leaves ; 

 sometimes in terminal spikes, from the leaves being reduced to bracts ; the uppermost 

 commonly staminale (with abortive pistils), the lowest fertile (with abortive stamens), and 

 the intermediate ones perfect. 



^1. Floiccrs oclandrous : carpels not ridged on the hack : leaves verticillate. 



1. Myriophyllum sriCATU.M, Linti. Spiked Water Milfoil. 

 Leaves all pinnately cut into capillary segments ; bracts shorter than the flowers, ovate, 



entire, the lowermost larger and serrate ; petals broadly ovate ; carpels smooth and even. — 

 Lirm. sp. 2. p. 992 ; MicJix. Jl. I. p. 190; Engl. bot. t. 83 ; Pursh, fl. 1. p. 274 ; Ell. sk. 

 2. p. 588 ; Torr. comp. p. 354 ; Bigel. Jl. Bost. p. 345 ; DC. prodr. 3. p. 68 ; Hook. Jl. 

 Bor.-Am. 1. p. 216 ; Torr. ^ Gr. Jl. N. Am. 1. p. 529. 



Stem varying in length with the depth of the water, sometimes 10 - 15 feet long, slender. 

 Leaves 3 - 5 in a whorl, all very finely cut. Flowers in an interrupted leafless spike, which 

 rises above the water ; the upper bracts or floral leaves entire, very small, but increasing in 

 length towards the lower part of the spike, where they are sharply serrate. 



Deep ponds and slowly flowing waters ; not common. July - August. 



2. Myriophyllum verticillatum, Linn. Whorled Water MilfoiL 



Lower leaves cut into capillary segments ; floral ones, or bracts, pectinately pinnatifid, 

 commonly much longer than the flowers ; petals oblong-obovate ; carpels smooth and even. — 

 Linn. sp. 2. p. 992 ; Michx. Jl. 2. p. 190 ; Engl. bot. t. 218 ; Pursh, Jl. \. p. 274 ; Ell. sk. 

 2. p. 588 ; Torr. compend. p. 355 ; DC. prodr. 3. p. 68 ; Torr. <^ Gr.Jl. N. Am. I. p. 529. 



Stem very long, stouter than in the preceding species. Submerged leaves all finely divided ; 

 those belonging to the emersed part of the stem, much smaller and pectinate. Flowers in a 

 leafy spike. Segments of the calyx much smaller than the petals, acute. Anthers oblong. 

 Stigmas large and thick ; the surface covered with purplish woolly hairs. 



Ponds and small streams ; rather common. July - September. 



^ 2. Floicers ietrandrous : carpels uith one or two ridges on the back : leaves verticillate. 



3. Myriophyllcm heterophyllum, Michx. Various-leaved Water Mil/oil. 



Stem thick ; lower leaves cut into capillary segments ; floral ones ovate or lanceolate, thick, 

 sharply serrate, crowded, usually 5 in a whorl ; petals oblong ; carpels minutely roughened, 

 slightly 2-ridged and tuberculale on the back. — Michx. Jl.2. p. \9\; Pursh, Jl. 1. p. 274 ; 

 Ell. sk. 2. p. 588 ; Torr. comp. p. 355 ; DC. prodr. 3. p. 69 ; Torr. ^ Gr. Jl. N. Am. 1. 

 p. 529. 



Stem very long ; much stouter, and the submerged leaves smaller, than in the preceding 



