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8 



THE CACTACEAH 



Order CACTALES 



I, 



PERESKIEAE 



flowers morro^r ksH^Xd Tj/u^'f^-l' P'''"'? ' """^^'^^'^e in some species compound; 

 tesTa ofredthil hr l^'''' "'""^ ^^''^ ="' '"=^'"'^'' g'°'='>'ds wanting; ovule with short funicle; 



remote 



similarity 

 r families. 



pi!".'f'r * ^!"l™:^'f ^^^ °f ^!^«^''' in the cactus family are doubtless the 



Pereskiopsis, some 



have different foliage and the areoles of t;; b^^^r "' ""^""^ "^^ 



Opunha whose species have leaves, though much reduced and usually c 



wise very different ; but some of the species of Opuniia were first referred 



Maihuema (two of whose species h^ve only recently blen t • " - 



similar but the areoles lack glochids, otherwise very 



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skia) 



This tribe has a wide geographic distribution? butTs Sd wUd^ ly in the tropics. 



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PERESKIA (Plumier) Miller 



V / -- ^ -y XVXX.1C1, ^ara. uict. Abr. ed. 4. 1754. 



P^-nt^li::s1nt^s:;rZ:^^^^^^ branching and resembling other woody 



(found only in the OpuntieL) wantL^-^t^^^^^^ "°^ barbed ; glochids 



flowers soHtary, cor^mbose/o7rScles Ter^^^^^^^^^ °' somewhat fleshy ; 



style single; stigma-lobes linear- ^^Slv !i^'"^^ or axillary wheel-shaped; stamens numerous; 



the eotyledons leafy; seedlings without sphies 



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Perennial, succulent plants, various in habit, mostly very spiny, characterized by specialized 

 organs termed areoles. Leaves usually none, except in Pereskia and Pereskiopsis, where they are 

 large and flat but fleshy, and in Opuntia and its relatives, where they are usually much reduced 

 and mostly caducous, terete, or subulate. Spines very various in size, form, arrangement, and 

 color, sometimes with definite sheaths. The areoles are peculiar and complex organs, situated in 

 the axils of leaves when leaves are present, and bearing the branches, flowers, spines, glochids, hairs, 

 or glands; in some genera two kinds of areoles occur, either distinct or united by a groove. Flowers 

 usually perfect, either regular or irregular, usually solitary but sometimes clustered, sometimes 

 borne in a specialized terminal dense inflorescence called a cephalium; perianth-tube none, or large 

 and long, the limb spreading or erect, short or elongated, the lobes few or numerous, often inter- 

 grading in shape and color, but sometimes sharply differentiated into sepals and petals ; stamens 

 commonly numerous, elongated or short, sometimes clustered in series, the filaments usually borne on 

 the throat of the perianth, the small oblong anthers 2 -celled; style one, terminal, short or elongated; 

 stigma-lobes 2 to many, usually slender; ovary i -celled, distinct, or immersed in a branch or 

 forming a part of a branch; ovules numerous. Fruit a berry, often juicy and sometimes edible, 

 sometimes dry, in one species described as capsular and dehiscing by an operculum, in others opening 

 by a basal pore. Seeds various; cotyledons two, accumbent, sometimes minute knobs, often broad 

 or elongated ; endosperm little or copious ; radicle terete. 



The order consists of the following family only: 



I 



Family CACTACEAE Lindley, Nat. Syst. ed. 2. 53. 1836. 

 Characters of the order as given above. The family is composed of three tribes. 



r 



Key to Tribes. 



Leaves broad flat; glochids wanting; flowers stalked (sometimes short-stalked), often dustcred i Pereskieae ^ 



Leaves (^^t - P.re.*,.^.,,) terete or subterete. usually small, often wanting on the vegetatfve parVs"; ' ' 



flowers sessile. 



^'^ti^h-i'ssf %L%l'K^^r; "" '" ^^"""^= """ ''^"'" -ii'i''i--^)V flowers '■ y'"'' 



^ ^ 3. Cereeae 



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