What's the difference between pigweed and pinweed?

Pigweed

Definition:

(n.) A name of several annual weeds. See Goosefoot, and Lamb's-quarters.

Example Sentences:

(1) Very low amounts of pigweed-type and nettle pollen appear in April.
(2) Weeds elicit two levels of allergenicity, a high level by the Ragweeds and other members of the Asteraceae, and a much lower level by members of the families Amaranthaceae (Pigweed, Western Water Hemp), Chenopodiaceae (Lamb's Quarters, Kochia, and Russian Thistle), and Plantaginaceae (Plantain) in the St. Louis, Missouri area.
(3) Leaves of 10 plant species, 7 with photorespiration (spinach, sunflower, tobacco, pea, wheat, bean, and Swiss chard) and 3 without photorespiration (corn, sugarcane, and pigweed), were surveyed for peroxisomes.
(4) Homogenates of pigweed leaves (no photorespiration) contained from one-third to one-half the activity of the glycolate pathway enzymes as found in comparable preparations from spinach leaves which exhibit photorespiration.
(5) In early August pollen counts begin to rise with the primary pigweed-type pollination season and the first ragweed pollen.
(6) With this method, similar antigenic determinants were found between short ragweed and giant ragweed, cocklebur, lamb's-quarter, rough pigweed, marsh elder, and goldenrod.
(7) Twenty-two young cows died or were euthanatized after intoxication associated with ingestion of redroot pigweed (Amaranthus retroflexus) growing in marginal grass pasture.
(8) Data from pigweed on the absence of photorespiration yet abundance of enzymes associated with glycolate metabolism is inconsistent with current hypotheses about the mechanism of photorespiration.
(9) Grand Rapids) and pigweed (Amaranthus albus L.) seeds.
(10) In contradistinction to Artemisia (sage), there are two exceptions such as in south China: In Shenghai, Ricinus (castor bean) and Humulus (Hops) are found to be the major offender instead of Artemisia (sage) and At Kwangzhou, Kwangdong province Wood Ephedra, Wild Amaranth (pigweed) are also found to be major offenders instead of Artemisia (sage).
(11) However, only traces of peroxisomal enzymes were separated by sucrose gradient centrifugation of particles from pigweed.
(12) A major weed pollen season (May through Dec.) consisted of ragweed, Mexican tea, pigweed, dog fennel, and false nettle.
(13) Rabbits fed Amaranthus retroflexus (redroot pigweed) did not develop lesions of renal toxicosis reported in other species fed this plant.