FLOWERING PLANTS AND FERXS OF ARIZONA 297 



1. Trianthema portulacastrum L., Sp. PL 223. 1753. 



Greenlee, Maricopa, Pinal, Cochise, and Pima Counties, 1,000 to 

 4.000 feet, July to October. Widely distributed in tropical and sub- 

 tropical America; Eastern Hemisphere. 



A common weed in irrigated land in southern Arizona, but easily 

 controlled by cultivation. Locally known as "pigweed," a name 

 applied to several unrelated plants. 



39. PORT! LACACEAE. Portulaca family 



Plants mostly herbaceous and small, annual or perennial, often 

 succulent; leaves entire; flowers perfect, regular but slightly asym- 

 metric; sepals commonly 2; petals mostly 4 or 5; stamens few or 

 numerous; style cleft or divided; ovary superior or partly inferior, 

 1-celled; fruit a circumscissile or longitudinally dehiscent capsule. 



Key to the genera 



1. Capsule circumscissile (2). 

 2. Calyx of 2 separate sepals, free from the ovary; capsule circumscissile near 

 the base and splitting upward longitudinally; plants subacaulescent, the 

 leaves mostly basal 3. Lewisia. 



2. Calyx 2-lobed, the tube adherent to the ovary; capsule circumscissile near 



'the middle, the calyx lobes coming away with the top of the capsule; 



plants caulescent, with leafy stems 7. Portulaca. 



1. Capsule valvate, splitting downward from the top \2>). 



3. Stigmas and valves of the capsule 2; inflorescence more or less scorpioid in 



flower; plants annual 4. Calyptridium. 



3. Stigmas and valves of the capsule 3; inflorescence not scorpioid (4). 



4. Sepals deciduous; plants perennial 1. Talixtjm. 



4. Sepals persistent (5). 



5. Stem leaves alternate; petals 5 to 7; stamens 5 to 12, usually more 



numerous than the petals; plants annual 2. Calaxdrixia. 



5. Stem leaves opposite; petals and stamens 5 (6). 



6. Plants perennial, with a large globose corm; stem leaves 1 pair, not 



connate 5. Claytoxia. 



6. Plants annual, or perennial with runners ending in bulblets; stem 

 leaves several pairs or, if 1 pair, then connate-perfoliato. 



6. Moxtta. 



1. TALIXUM 



Plants perennial, glabrous; stems leafy or scapose; leaves alternate, 

 the blades broad and flat, to narrow and nearly terete; inflorescence 

 paniculate or cymose; stamens 5 to numerous; style 3-cleft; ovary 

 superior. 



Key to the species 



1. Blades of the lower leaves 1 to 5 cm. wide, flat; inflorescence a many-flowered 

 elongate open panicle, its leaves mostly reduced to small bracts; petals 

 commonly pink, not more than 6 mm. long; flowering stems 25 cm. long or 



longer, from a thick tuberous root 1. T. paxiculatum. 



1. Blades of all of the leaves less than 5 mm. wide; inflorescence a few-flowered 

 cyme, or the flowers solitary in the leaf axils (2). 

 2. Flowers in terminal cymes; petals pink (3). 



3. Stamens 10 or more; stems and scapes spreading, less than 10 cm. long. 



2. T. YALiDn.rM. 

 3. Stamens 4 to 8; stems and scapes erect or ascending, commonly at least 

 10 cm. long (4). 

 4. Sepals obtuse to short-acuminate, not or obscurely cuspidate. 



3. T. PARVIFLORUM. 



4. Sepals bearing a stout, erect, apical-dorsal, hornlike cusp. 



4. T. GOODDINGII. 



