Asclepiadaceae| Calotropis gigantea| Taxonomy| | Dr. Jayarama Reddy| St. Joseph's University| Join скачать в хорошем качестве

Asclepiadaceae| Calotropis gigantea| Taxonomy| | Dr. Jayarama Reddy| St. Joseph's University| Join

Asclepiadaceae: Plants herbs, shrubs, mostly twiners and rarely trees; leaves opposite, simple, entire margin rarely alternate; inflorescence cymose or racemose; flowers hermaphrodite, pentamerous; calyx of 5 sepals, imbricate; petals 5, gamopetalous, corona arising as outgrowth of petals or stamens; stamens 5, fused with stigmatic disc forming gynostegium; pollens forming pollinia; carpels bicarpellary, syncarpous, ovaries and style free, only stigma fused to form disc, marginal placentation, fruit follicles. Perennial herbs (Asclepias) or shrubs (Calotropis, Leptadenia), Stem: Herbaceous, week and climbing or succulent, woody below (Calotropis), erect, twiner or climbers (Cryptostegia) cylindrical, rarely hairy and solid, latex present. Leaves: Simple, petiolate, exstipulate, entire, opposite rarely whorled, waxy; in Dischidia rafflesiana leaves are modified into pitchers, reduced or absent (Periploca), succulent in Hoya. B. Floral characters: Inflorescence: Mostly umbellate cymes (Calotropis) or dichasial cyme ending in monochasial cyme. Flower: Bracteate or ebracteate, pedicellate, complete, hermaphrodite, actinomorphic, rarely zygomorphic (Ceropegia), pentamerous, hypogynous. Calyx: Sepals 5, polysepalous or gamosepalous-fused near the base, quincuncial aestivation, sometimes valvate. Corolla: Petals 5, gamopetalous, 5 lobed, twisted aestivation or valvate, corona may be scaly or hairy out growth from petals – corolline corona in Cryptostegia, Cryptolepis or form staminal tube i.e. staminal corona in Calotropis and Asciepias. Androecium: Stamens 5, synandrous, gynostegium (stamens fused with stigmatic disc to form gynostegium), anthers dithecous, epipetalous, coherent; the pollen grains of each half anther usually agglutinated into granular mass of tetrads or waxy pollen called pollinium (Asclepias, Calotropis). Thus each stamen has two pollinia. The pollinia of two adjacent anther halves are connected together at the black, dot-like gland called corpusculum by appendages called – retinacula. The two pollinia (of adjacent anther halves), two retinacula and a corpusculum together form a single translator. So in all there are 5 translators. Gynoecium: Bicarpellary, syncarpous, ovaries free, superior, enclosed in staminal tube, ovules many on marginal placentation, each carpel is unilocular; style 2, free, distinct; stigmas united to form a pentangular disc with which anthers are fused to form gynostegium. Fruit: An etaerio of two, often widely divergent follicles; in some one follicle is abortive.