156 ELEAGNACEAE (OLEASTER FAMILY) 



OPUNTIA (OPUNTIA) 



" Eyes " spine-bearing. Flowers lateral. Calyx lobes spreading. Ovary 

 cylindric. Fruit pear-shaped. (Grew in Greece near the town of Opun- 

 tia.) 



A. Joints of the stem decidedly flattened; spines 8-15 from the same place. E. 



O. polycantha (SPINY OPUNTIA) 



AA. Joints of the stem ovate or subglobose, nearly terete; spines 1-4 from the same 

 place. W. E. O. fragilis (FRAGILE OPUNTIA) 



ELEAGNACEAE (OLEASTER FAMILY) 



Shrubs, silvery-scaly or stellate-pubescent. Leaves opposite. Flow- 

 ers imperfect, clustered or rarely solitary. Perianth of pistillate 

 flowers tubular or urn-shaped below; limb 4-cleft, deciduous. 

 Corolla none. Stamens 8. Ovary i -celled. Fruit drupelike, 

 red. Seed i. W. C. E. (Honor of J. Shepherd, curator of the 

 Liverpool Botanic Gardens.) Shepherdia canadensis (SOAP-OLALLEE) 



LYTHRACEAE (LOOSESTRIFE FAMILY) 



Herbs; stem 4-angled. Leaves opposite or alternate. Flowers 

 perfect. Calyx persistent, free from the ovary but usually inclos- 

 ing it, toothed. Petals as many as the sepal teeth of the calyx. 

 Stamens various in number, on the calyx. Ovary i-6-celled; style 

 i. Fruit a capsule. 



A. Calyx tube campanulate, 4-striate; leaves all opposite, not rounded at base. 



B. Leaves linear-lanceolate, sessile, cordate-auricled and somewhat clasping at 



base; capsule bursting irregularly. W. E. (Honor of P. Ammann, a German 



botanist.) Ammania coccinea 



BB. Leaves oblong or linear-oblong, sessile or petioled, narrowed at base, not 



auricled nor clasping; capsule septicidal. E. (Diminutive of L. rota = a 



wheel; referring to whorled leaves of some species.) Rotala ramosior (ROTALA) 



AA. Calyx tube cylindric, 8-i2-striate; leaves alternate or the lower opposite, 



sessile, rounded at base, not clasping. W. (Gk. lythron = blood; from the 



purple flowers of some.) Lythrum hyssopifolium (LOOSESTRIFE) 



ONAGRACEAE (EVENING-PRIMROSE FAMILY) 



Herbs. Leaves simple, alternate or opposite; stipules none or 

 mere glands. Flowers perfect, regular or irregular. Calyx tube 

 adherent to the ovary, often prolonged beyond it; calyx limb 

 2-6-lobed, but usually 4-lobed. Petals o or 2 or 4. Stamens usually 

 as many or twice as many as the sepals. Ovary inferior, 1-6- 

 celled; style i. Fruit a capsule or nutlet. 



