146 CALLITRICHACEAE (WATER STARWORT FAMILY) 



B. Plant pubescent; seed black. E. — Considered poisonous. 



E. maculata (milk spurge) 

 BB. Plant glabrous; seed gray. 

 C. Seed with 5-6 sharp transverse ridges; leaves linear-oblong to ovate. E. 



E. glyptosperma (ridge-seed spurge) 

 CC. Seed pitted and somewhat transversely wrinkled; leaves oblong to spatulate. 

 W. E. E. serpyllifolia (thyme-leaved spurge) 



AA. Stems erect or nearly so; involucre glands without petal-like appendages. 

 D, At least the upper leaves serrulate. 



E. Seed pitted; glands with hornlike projections. 17. E. crenulata 

 EE. Seed reticulate; glands blunt. E. E. dictyospenna (net-seed spurge) 



DD. Leaves entire. 



F. Leaves round-obovate; umbel 3-rayed. W. E. peplus (pretty spurge) 

 FF. Leaves linear to oblong; umbel 4- to many-rayed. 



G. Seed usually wrinkled; leaves linear to oblong. W. 



E. lathyrus (caper spurge) 

 GG. Seed smooth; leaves filiform. E. E. cyparissias (cypress spurge) 



CALLITRICHACEAE (Water Starwort Family) 



Herbs, acquatic, or rarely terrestrial in mud; stem slender or 

 capillary. Leaves opposite, spatulate or linear; stipules none. 

 Flowers minute, axillary, rarely found. Perianth none. Bracts 

 none, or 2 and saclike. Stamen i. Pistil i. Ovary 4-celled; 

 styles 2. Fruit 4-lobed, 4-seeded. — (Gk. kalos = beautiful, trichos 

 = hair; from the slender stem.) Only the following genus. 



(F. & R. p. 246.) Callitriche (water starwort) 



EMPETRACEAE (Crowberry Family) 



Shrubs, low; branches densely leafy. Leaves small, narrow, 

 entire, evergreen, nearly sessile, channeled on the lower side by 

 the revolute margins; stipules none. Flowers small, dioecious or 

 monoecious or polygamous, axillary. Sepals 3. Petals 2-3, or 

 none. Stamens 2-4. Ovary 6-9-celled; style 6-9-lobed. Fruit 

 berrylike, black or red, containing 6-9-nutlets. W. C . — (Gk. 

 zn = upoUj petros = a rock; often growing in rocky places.) 



Empetrum nigrum (crowberry) 



LIMNANTHACEAE (False-mermaid Family) 



Herbs, annual, glabrous. Leaves alternate, pinnately-dissected 

 or -compound; stipules none. Flowers solitary, regular, perfect. 

 Calyx tube saucer-shaped. Sepals 2-5, persistent. Petals 2-5. 

 Stamens 4-10, somewhat perigynous. Styles united to near the 

 top, basal, central between the ovaries; stigmas 2-5. Carpels 2-5, 

 almost distinct, indehiscent, i-seeded. — In wet places. 



