This weed from western Asia is locally frequent in southwestern states, especially on saline soils, but it is rare in the southeast (K, W). There is one Ky. record., a coll. from BALL by C.C. Deam (IN): #60135, 1940 Sep 14 , "In a fallow field bordering Turner Lake about 8 miles northwest of Bandana . Frequent over an area of a square rod" [about 25 square meters]. It was initially identified as P. exsertum Small, a synonym of P. prolificum. It differs from congeners in Ky. as follows (FNA 5, W): inflorescences spikelike (versus axillary), the cymules borne in the axils of bracts shorter than the cymules (versus in the axils of leaves longer than the cymules though often shorter than primary leaves of the stem). It appears most similar to ramosissimum and prolificum but differs as follows: margins of tepals pink, rarely red or white (versus greenish yellow or yellow, rarely pink or white); achenes 1.3-2.3 mm (versus 2.3-3.5 mm).