Glossary of Plant Systematics (1st ed.) by Simpson (2006)
- (a) Alternate, with points of attachment in more than three rows/ranks. Syn: polystichous. (arrangement) (b) Perianth parts arranged in a spiral, one per node, not in distinct whorls. (perianth arrangement) (c) Stamens arranged in a spiral, one per node; not whorled. (stamen arrangement) (c) A type of endothecium in which the secondary wall thickenings are spiral or helical in shape.