260 Lythraceae 



4. O. prolifera Engelm. Stems 1-3 m. high, much branched 

 and often forming thickets, with reticulated wood ; joints cylin- 

 dric, dark green, 7.5-15 cm. long, 3.5-5 cm. thick ; pulvini tomen- 

 tose and the older with fine straw-colored bristles ; spines 8-10, 

 variable, with large loose yellowish or rusty sheaths, 2.5-3.5 cm. 

 long, 1 subcentral, the others stellate-spreading; flowers dark 

 red, 3.5 cm. broad; fruit clavate to subglobose, strongly tubercu- 

 late like the joints, often proliferous; seeds large, 6 mm. broad 

 with broad commissure. 



Common about San Diego. Known in our region only at San Pedro, where 

 it is growing on bluffs near the bay. 



Family 63. LYTHRACEAE. LOOSESTRIFE FAMILY. 



Herbs or shrubs, often trees in tropical regions, mostly 

 with opposite leaves and solitary or clustered perfect 

 flowers. Stipules usually none. Calyx persistent, free 

 from the ovary, but generally enclosing it, the limb 

 toothed and often with accessory teeth in the sinuses. 

 Petals as many as primary calyx-teeth or none. Sta- 

 mens various, inserted on the calyx ; anthers versatile, 

 longitudinally dehiscent. Ovary 2-6-celled, or some- 

 times 1-celled ; style 1 ; stigma capitate, 2-lobed ; ovules 

 many, rarely few, anatropous. Capsule 1-several-celled, 

 variously dehiscent or sometimes indehiscent. Endo- 

 sperm none ; cotyledons flat, often auricled at base. 



Calyx-tube campanulate or hemispheric. 1. AMMANNIA. 



Calyx-tube cylindric. 2. LYTHRUM. 



1. AMMANNIA L. 



Annual glabrous or glabrate herbs, mostly with 

 4-angled stems, opposite sessile narrow leaves, and small 

 axillary solitary or clustered flowers. Calyx campanu- 

 late, globose or ovoid, 4-angled, 4-toothed, often with 

 small accessory teeth in the sinuses. Petals 4, decidu- 

 ous. Stamens 4-8, inserted on the calyx-tube ; fila- 

 ments slender or short. Ovary enclosed in the calyx- 

 tube, nearly globose, 2-4-celled, bursting irregularly. 



