Seed when castor beans have been ingested by animals. In addition, seeds containing amygdalin—apple, apricot, bitter almond, peach, plum, cherry, quince, and others—when consumed in sufficient amounts, may cause cyanide poisoning. Other seeds that contain poisons include annona, cotton, custard apple, datura, uncooked durian, golden chain, horse-chestnut, larkspur, locoweed, lychee, nectarine, rambutan, rosary pea, sour sop, sugar apple, wisteria, and yew. The seeds of the strychnine tree are also poisonous, containing the poison strychnine. The seeds of many legumes, including the common bean ("Phaseolus vulgaris"), contain proteins called lectins which can cause gastric distress if the beans are eaten without cooking.
Genus (mathematics) manifold of complex points). For example, the definition of elliptic curve from algebraic geometry is "connected non-singular projective curve of genus 1 with a given rational point on it". By the Riemann-Roch theorem, an irreducible plane curve of degree "d" has geometric genus where "s" is the number of singularities when properly counted. Genus can be also calculated for the graph spanned by the net of chemical interactions in nucleic acids or proteins. In particular, one may study the growth of the genus along the chain. Such a function (called the genus trace) shows the topological complexity and domain structure