586 REPORT OF NEW JERSEY STATE MUSEUM. 



Fl. — Mid-June to late Jul}-. Fr. — Late July to early Sep- 

 tember. 



Middle District. — Farmingdale, New Egypt, Arney's Mt. (S), Camden Co. 

 (CP), Mickleton (H), Swedesboro. 



Family HALORAGIDACE^. Water-milfoils. 

 Key to the Species. 



0. Flowers perfect, the parts in threes, petals none, plant growing on mud 

 or in shallow water, 2-5 dm. long. 



b. Leaves with flowers in their axils, lanceolate, serrate ; those without 

 flowers usually pectinate. Proserpinaca palnstris, p. 586 



bh. Leaves all pectinate. P. pectinata, p. 587 



•«. Flowers monoecious or dioecious, the parts in fours ; plant usually float- 

 ing in water with leaves often whorled and finely divided. When grow- 

 ing on mud, plant very small with leaves reduced. 

 b. Flowering stems practically naked, accompanied by nearly naked, up- 

 right sterile stems, leaves, when present, filiform, undivided, growing 

 upright in shallow water, 7-35 cm. high. Myriophyllum tenellum, p. 587 

 bb. Flowering stems leafy. 



c. Flowers on the axils of unmodified foliage leaves. 



Carpels smooth and plump. M. humile, p. 588 



dd. Carpels with prominent, irregular dorsal ridges. 



M. pinnatum, p. 588 

 cc. Flowers in terminal naked spikes or in the axils of greatly reduced 

 and modified leaves. 

 d. Leaves in definite whorls, carpels papillose, roughened. 



M. heterophyllum, p. 588 



dd. Leaves variously arranged on the same plant, carpels with 



irregular dorsal ridges. M. pinnatum, p. 588 



PROSERPINACA L. 



Proserpinaca palustris L. Mermaid-weed. 



Proserpinaca palustris Linnxus, Sp. PI. 88. 1753 [Virginia]. — Barton, Fl. 

 Phila. L 76. 1818.— Britton 105.— Keller and Brown 234. 



Occasional in swamps in the northern counties; locally in the 

 Middle district and common along the Coastal strip to Cape May. 



Mr. K. K. Mackenzie has described as P. intermedia (Torreya 

 1910, p. 250) a plant from half way between Barnegat Pier and 

 Island Heights Jnc, which has the emersed fruiting leaves pec- 

 tinate with a broad marginal rachis. P. palustris regularly puts 

 forth shoots with this sort of leaves late in the season or where 

 the water in which it grows becomes dried up, and I am by no 

 Bieans convinced that this is not a form of this species, in which 



