810 LOASACEAE 



Order 22. OPUNTIALES. 



Succulent herbs, shrubs or trees, armed with spines, leafless or essentially so, 

 or rigid leafy herbs, furnished with more or less specialized hairs. Flowers 

 perfect. Hypanthium present. Calyx of 4 or 5, or many sepals. Corolla of 

 4 or 5, or many petals. Androecium of usually numerous stamens in several 

 series or groups, and often partially reduced to staminodia. Gynoecium of 4 or 

 2-several united carpels. Ovary inferior. Fruit baccate or capsular. 



Sepals and petals 4 or 5 each, very different: leaves entire or dissected: erect or climbing plants, with 

 rigid hairs. Fam. 1. LOASACEAE. 



Sepals and petals nearly alike, at least the latter numerous: leaves typically 



mere scales or wanting: succulent plants, usually armed with spines. Fam. 2. OPUNTIACEAE. 



FAMILY 1. LOASACEAE Reichenb. LOASA FAMILY. 



Herbs or rarely shrubs, with barbed or stinging rigid hairs. Leaves oppo- 

 site or alternate, without stipules: blades entire, lobed or pinnatifid. Flowers 

 regular. Hypanthium straight or spirally twisted. Sepals often persistent. 

 Corolla white, yellow or red. Petals sessile, or with claws. Androecium of 

 numerous stamens or rarely of only 5. Filaments filiform, often accompanied 

 by filiform or petal-like staminodia. Gynoecium of 2-5 united carpels. Ovary 

 1-celled. Fruit a ribbed or angled straight or spiral capsule. Seed with a 

 membranous, cellular or reticulated testa. 



Stamens numerous: style lobed: capsules several-many-seeded. 



Filaments inserted below the petals: style 3-lobed: placentae 3. 



Outer filaments not petal-like: seeds in 1 row, ascending, angled, wingless. 1 . MENTZELIA. 

 Outer filaments petal-like: seeds in two rows, horizontal, flattened, winged. 2. NUTTALLIA. 

 Filaments inserted with the petals and adnate to their bases: style 5-lobed: 



placentae 5. 3. EUCNIDK. 



Stamens 5: style entire: capsules 1-seeded. 4. CEVALLIA. 



1. MENTZELIA L. 



Annual, biennial or perennial mostly diffuse or reclining herbs. Leaf-blades 

 relatively broad, sinuate, or lobed. Androecium without staminodia. Seeds angled, 

 wingless. 



Flowers and capsules sessile in the forks of the branches: petals abruptly pointed. 1. M. oligosperma. 

 Flowers and capsules short-pediceled : petals truncate and often with a minute 



apiculation. 2. M. Floridana. 



1. Mentzelia oligosperma Nutt. Leaf -blades 1.5-6 cm. long, ovate to oblong, 

 coarsely toothed and sometimes slightly lobed: sepals linear to narrowly linear- 

 lanceolate: petals light yellow, 8-10 mm. long: capsules 1.5-2 cm. long. 



In dry soil, Illinois to Colorado, Louisiana, Texas and Mexico. Spring and summer. 



2. Mentzelia Floridana Nutt. Leaf -blades 2-9 cm. long, ovate to deltoid-ovate, 

 toothed and 3-lobed: sepals lanceolate, often with a very broad base: petals golden 

 yellow, 15-18 mm. long: capsules 1-1.5 cm. long. 



In hammocks, southern peninsular Florida and the Keys. Also in the Bahamas. 

 All year. 



2. NUTTALLIA Raf. 



Herbs with pubescence like that of Mentzelia, usually erect. Leaf-blades rela- 

 tively long and narrow, sinuate or pinnatifid. Androecium with staminodia in the 

 outer series. Seed-body flattened. [Touteria Eaton & Wright.] Summer. 



Petals less than 1 cm. long: sepals about % as long as the capsule. 1. T. Wrightii. 

 Petals over 1 cm. long: sepals about ^ as long as the capsule. 



Petals 1.5-2 cm. long: capsules about 5 mm. thick. 2. T. multiflora. 



Petals 2.5-3.5 cm. long: capsules about 10 mm. thick. 3. T. stricta. 



1. Nuttallia Wrightii (A. Gray) Greene. Stems somewhat corymbose above: 

 blades of the stem-leaves oblong to lanceolate, 2-8 cm. long, sinuate: sepals lanceo- 

 late: petals ochroleucous, 5-8 mm. long, obtuse: capsules 2-2.5 cm. long. 



In dry soil, Texas and New Mexico. 



2. Nuttallia multiflora (A. Gray) Greene. Stems widely corymbose: leaf- 

 blades pinnatifid, the teeth narrow, mainly acute: petals golden yellow, abruptly 

 pointed: capsule slender. 



In dry or stony soil, Colorado to Texas and New Mexico. 



