270 



HALORAGIDACEAE. 



Family 8. HALORAGIDACEAE Kl. & Garcke, 



Water-jMilfoil Family. 



Perennial or rarely annual herbs, mainly aquatic, with alternate or ver- 

 ticillate leaves, the submerged ones often pectinate-pinnatifid. Flowers 

 perfect, or monoecious, or dioecious, axillary, in interrupted spikes, solitary 

 or clustered. Calyx-tube adnate to the ovary, its limb entire or 2-4-lobed. 

 Petals small, 2-4, or none. Stamens 1-8. Ovary ovoid-oblong, or short- 

 cylindric, 2-8-ribbed or winged, 1-4-celled ; styles 1-4 ; stigmas papillose or 

 plumose. Fruit a nutlet, or dnipe, compressed, angular, rbibed or winged, 

 indehiscent, of 2-4 1-seeded carpels. Endosperm fleshy ; cotyledons minute. 

 Eight genera and about 100 species, of wide distribution. 



1. PROSERPINACA L. 



Aquatic herbs, with simple stems. Leaves alternate, lanceolate, dentate 

 or pectinate-pinnatifid. Flowers perfect. Tube of the calyx adnate to the 

 triquetrous ovary, the limb 3-4-parted. Petals none. Stamens 3 or 4. Styles 

 3 or 4, eylindric or conic-subulate, stigmatic above the middle. Fruit bony, 



3-4-celled, with 1 seed in each cavity. 

 Four known species, natives of eastern N. 

 the following typical. 



[Middle Latin, forward-creeping.] 

 Am., extending to the West Indies, 



1. Proserpinaca palustris L. 



Mermaid-weed. (Fig, 292.) 



Glabrous, simple or sometimes 

 branched, l°-2° long. Emersed 

 leaves, 1-2' long, l'-6" wide, 

 sharply serrate, the submerged 

 ones pectinate-pinnatifid into stiff 

 linear acute segments which are 

 often serrulate, bearing a minute 

 black spine in their axils; flowers 

 solitary or several together, ses- 

 sile in the axils of the emersed 

 leaves; fruit about 2" long, the 

 faces concave, smooth or rugose. 



In water, Pembroke and Devon- 

 shire Marslies. Native. Eastern 

 United States. Flowers nearly 

 throughout the year. Probably 

 brought from the continent by a bird. 



Order 27. AMMIALES. 



Herbs, shrubs or trees, almost always with petaliferous flowers. Calyx- 

 segments and petals usually 5. Stamens 4 or 5. Ovary inferior, adnate 

 to the calyx, compound ; ovule 1 in each cavity. 



