538 LIMNANTHACEAE 



pinnate, glabrous; divisions 3-5, oblong or oblanceolate to nearly linear, 5-15 



mm. long; sepals ovate, 2 mm. or in fruit 3 mm. long; petals oblanceolate or 



oblong, usually less than 1 mm. long; carpels usually 2. Wet places: Colo. 

 Wyo. Calif. Wash. 



FAMILY 71. ZYGOPHYLLACEAE. CALTROP FAMILY. 



Perennial herbs, shrubs, or trees, with articulate stems. Leaves alter- 

 nate or opposite, digitate or evenly pinnate, with inequilateral punctate 

 leaflets. Flowers perfect, regular or nearly so. Sepals 5, rarely 4 or 6, 

 usually imbricate. Petals as many, hypogynous. Stamens twice as many. 

 Gynoecium of 2-5 united carpels; ovary 2-5-celled, rarely 10-12-celled, 

 angled or winged; styles wholly united. Fruit a capsule or splitting into as 

 many or twice as many nutlets as there are carpels. 



Leaves digitately 1-7-foliolate ; stipules spiny; stamens with scale-like appendages. 



1. FAGONIA. 

 Leaves abruptly pinnate; stipules in ours not spiny. 



Shrubs with endosperm; fruit woolly; stamens with scale-like appendages. 



2. COVILLEA. 



Herbs without endosperm; corolla mostly yellow; stamens without scale-like appen- 

 dages. 



Fruit dividing into 5 (by abortion sometimes fewer) carpels, each with 3-5 one- 

 seeded compartments, spiny. 3. TRIBULUS. 



Fruit dividing into 8-12 (twice as manj- as the original carpels) one-seeded nutlets, 

 merely tubercled. 4. KALLSTROEMIA. 



1. FAGONIA L. 



Branching, diffuse, spreading, or prostrate undershrubs. Stems spinulose on 

 the upper angles. Leaves opposite, digitately 1-7-foliolate; leaflets entire, 

 callous-mucronate or spinulose-tipped; stipules often spinescent. Flowers 

 solitary, pedunculate. Sepals 5, imbricate, caducous. Petals 5, imbricate, 

 unguiculate, caducous. Stamens 10; filaments filiform, naked. Style subulate; 

 stigma simple; ovary 5-celled. Fruit pyramidate-ovoid, deeply 5-angled, the 

 1-seeded carpels at length separating from the axis and dehiscing on the inner 

 edge. 



1. F. calif ornica Benth. A low dichotomously branched undershrub; 

 stems 2-5 dm. long, diffuse, much branched, glabrous; stipules 2-5 mm. long, 

 arcuate-spreading; leaflets 3, lanceolate or ovate-lanceolate, glabrous or nearly 

 so, 3-10 mm. long; petals spatulate, 5-8 mm. long; fruit ovate or spindle-shaped 

 in outline, 4-5 mm. long, 7-8 mm. broad, finely pubescent. Sandy soil: Calif. 

 s Utah. Sonora L. Calif. L. Son. 



2. COVILLEA Vail. CREOSOTE BUSH, HEDIONDILLA. 



Low, evergreen, strong-scented, balsamiferous shrubs. Leaves opposite, 

 consisting of a single pair, rarely of several pairs of small inequilateral leaflets; 

 stipules persisting. Peduncles 1 -flowered. Sepals 5, imbricate, unequal, caducous. 

 Petals 5, yellow, obovate or lanceolate-spatulate, more or less unguiculate. 

 Stamens 10, inserted on the base of the small disc. Anthers oblong. Pistil of 5 

 united carpels. Ovary short-stipitate, globose, pilose, 5-celled, the cells alternate 

 with the petals; styles united, sometimes separable. Fruit villose or tomentose, 

 globose, 5-angled. [Larrea Cav., not Ort.] 



1. C. glutinosa (Engelm.) Rydb. A diffusely branched resinous shrub, 

 1-3.5 m. high; stems densely leafy, angled, silky-pubescent; leaves nearly sessile; 

 leaflets obliquely lanceolate or lunate, falcate, 5-10 mm. long, coriaceous, resinous, 

 yellowish, silky-pubescent, becoming glabrate, 3-ribbed; petals slightly unguicu- 

 late, spatulate-oblong, bright yellow; fruit subglobose or elliptic, 4-5 mm. broad, 

 densely rusty- villous. L. glutinosa Engelm. L. mexicana Torr., not Moric. 

 C. tridentata Vail, in part. Dry plains and hills: Tex. s Utah Calif.; n Mex. 

 L. Son. 



