OPUNTIACEAE. 97 



1. P. suberosa L. Twigs glabrous or minutely pubescent: leaf -blades entire 

 to 3-lobed, mostly 2-10 cm. long: cymes 1-f ew-flowered : sepals linear to 

 lanceolate or oblong, 4-6 mm. long : corolla wanting : crown mostly blue-tinged : 

 berries 6-10 mm. in diameter: seeds about 3 mm. long. Pinelands and ham- 

 mocks, U. keys, L. keys, L. S. keys. [E. K.] (Ber., Bah., Cuba, Ant.) 



2. P. multiflora L. Twigs velvety: leaf -blades oblong or nearly so, 5-12 cm. 

 long, entire, rugose beneath: sepals 5-6 mm. long: petals linear or nearly so: 

 berries subglobose, 6-8 mm. in diameter. Hammocks, U. keys. (Bah., Cuba.) 



Order OPUNTIALES. 



Succulent, typically spine-armed, herbs, shrubs, or trees, mainly 

 leafless or essentially so, or leafy rigid herbs, 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 many 

 stamens, in several series or groups, sometimes partially reduced to 

 staminodia, Gynoecium of 4, or 2-several, united carpels. Ovary in- 

 ferior. Fruit baccate or capsular. 



Sepals and petals 4 or 5 each, very different : leaves with entire or dissected blades : 

 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. LOASA FAMILY. 



Rigid herbs with barbed or stinging hairs. Leaves with entire lobed, 

 pinnatifid, or dissected blades. 



1. MENTZELIA [Plum.] L. Brittle-stemmed, mostly diffuse or reclining 

 herbs. Leaf-blades relatively broad, sinuate or lobed. Androecium without 

 staminodia. Seeds angled. 



1. M. floridana Nutt. Leaf -blades 2-9 cm. long, ovate to deltoid-ovate, toothed 

 and 3-lobed: sepals lanceolate, often very broad at the base: petals golden- 

 yellow, 15-18 mm. long: capsules 1-1.5 cm. long. Hammocks, U. keys, L. keys. 

 [E. K.](Bah.) 



FAMILY 2. OPUNTIACEAE. CACTUS FAMILY. 



Succulent plants, typically spine-armed, and often with cushions of 

 bristles or hairs at the base of the spines. Leaves mostly wanting, obso- 

 lete, or rudimentary. 



Stems not jointed : leaves none or obsolete : areolae without barbed bristles : flowers 



nocturnal : perianth campanulate. 

 Plants prostrate, reclining, or climbing : stems angled. 



Berry spiny : plants without aerial roots. 1. ACANTHOCEHEUS. 



Berry scaly : plants with aerial roots. 2. HTLOCEBEUS. 



Plants erect : stems and branches columnar, grooved. 



Flowers short-campanulate : perianth green-purple : 



style exserted : berry smooth. 3. CEPHALOCEEEUS. 



Flowers long-campanulate : perianth white : style in- 

 cluded : berry scaly. 4. HAERISIA. 

 Stems jointed : leaves scale-like, deciduous : areolae with 



barbed bristles : flowers diurnal : perianth rotate. 5. OPUNTIA. 



1. ACANTHOCEREUS Britt. & Eose. Plants with erect or reclining 

 stems and branches, the 3-6 angles low, the areolae remote, with several spines 

 Flora of Florida Keys 7. 



