Unground Vanilla— The linear,flattened capsule,from 12to 35cm in length and from 5to 9mm in width,has an apex terminating in a flat,circular scar and a gradually tapering base which is more or less curved or hooked,or in Tahitian vanilla,broad in the middle and tapering toward either end,the base closely resembling the summit.It is flexible and tough,nearly black,dusky brown to moderate brown externally,longitudinally wrinkled,moist,glossy,and occasionally has efflorescence of acicular or prismatic crystals of vanillin.Internally it is unilocular,with a brownish black pulp and numerous minute seeds.Occasional capsules are split near the summit into three parts.

Histology— The epidermis has a distinct cuticle and occasional stomata.The epidermal cells contain red to brown bodies and occasional prisms of calcium oxalate or crystals of vanillin.It has a collenchyma layer of one or two rows of cells,a thick sarcocarp composed of parenchyma and an interrupted circle of fibrovascular bundles,the latter leptocentric with a few vessels,and an outer circle of fibers with thin,strongly lignified walls and numerous transverse simple pits.The vessels with walls have slit-like pits or spiral thickenings;the parenchyma cells are usually thin-walled and deeply undulate,some thick-walled with oblique,slit-like pits or broad spiral bands,and contain occasional bundles of acicular crystals of calcium oxalate,up to 400µm in length,or a thin protoplasmic layer enclosing numerous oil globules.It has an endocarp composed of placental and interplacental regions;the placental region consists of six bifid placentas extending into the cavity of the fruit and bears irregularly trianguloid,black to reddish,flattened seeds,up to about 250µm in diameter,having a deeply reticulate seed coat;the interplacental regions show long,nearly straight hairs more or less matted together by their gummy,resinous secretion.

Powdered Vanilla— It is dusky brown to nearly black.The principal elements of identification are fragments of parenchyma of the sarcocarp with long,oblique,slit-like walls or broad spiral bands,calcium oxalate crystals of acicular outline and up to 400µm in length,and monoclinic prisms up to 35µm in length.It has numerous unicellular,nearly straight,glandular hairs,fragments of the seed coat with polygonal stone cells,and slender crystals of vanillin.