Question: Which genus of monocots native to the hot and arid regions of Mexico, features the genus plant Polianthes?

Context paragraphs:
Swainsona formosa: Swainsona formosa, Sturt's Desert Pea, is an Australian plant in the genus "Swainsona", named after English botanist Isaac Swainson, famous for its distinctive blood-red leaf-like flowers, each with a bulbous black centre, or "boss".  It is one of Australia's best known wildflowers.  It is native to the arid regions of central and north-western Australia, and its range extends into all mainland Australian states with the exception of Victoria.

Agave: Agave (US: , UK: , , Anglo-Hispanic: ) is a genus of monocots native to the hot and arid regions of Mexico and the Southwestern United States.  Some agave species are also native to tropical areas of South America.  The plants are perennial, but each rosette flowers once and then dies (see semelparity).  Some species are known by the name "century plant".

Argemone albiflora: Argemone albiflora, the white prickly poppy, also known as the bluestem prickly poppy or the Texas prickly poppy, is a small erect plant with a decorative white flower with a yellow latex.  It is deeply rooted with yellow or red stamens.  The plant is known for the sharp prickles on its stem and leaves.  The sepals fall off as the flower of this plant grows bigger.  It grows in the arid regions of the southern Midwest along roadsides and disturbed pieces of land.  Native Americans have long revered this plant for its medicinal and other uses.

Caulanthus: Caulanthus is a genus of plants in the mustard family.  Plants of this genus may be known as jewelflowers.  They are also often referred to as wild cabbage, although this common name usually refers to wild variants of "Brassica oleraceae", the cabbage plant.  Jewelflowers are native to the southwestern United States and northern Mexico, where they are often found in warm, arid regions.  Many species have an enlarged, erect stem rising from a basal rosette of leaves.  Flowers arise directly from the surface of the stem; many species have colorful, bell-shaped flowers.  The best-known of the fourteen species is probably the desert candle.

Cucurbita cordata: Cucurbita cordata is a species of flowering plant in the squash family.  It is similar to "Cucurbita californica", "Cucurbita cylindrata", "Cucurbita digitata", and "Cucurbita palmata" and all these species hybridize readily.  These species form the only restricted xerophyte species group in the genus "Cucurbita".  Each member of this species group is native to the Southwestern United States and Northwestern Mexico where they are relatively uncommon.  Each group member is found in hot, arid regions with low rainfall.  They prefer soil that is loose, gravelly, and well-drained.  "C. cordata" is found only in the vicinity of Bahía de los Ángeles, Baja California.  Botanists Bemis and Whitaker suggest that "C. cordata" and "C. cylindrata" may be a case of sympatric speciation.  The juvenile leaves of "C. cylindrata", "C. cordata", "C. digitata", and "C. palmata" show a high degree of similarity, but their mature leaves are visibly different, as are their root structures.  "C. cordata" fruits are gray green, striped, and round.

Polianthes: Polianthes is a genus of plants in family Asparagaceae, subfamily Agavoideae.  It includes tuberose ("Polianthes tuberosa"), a plant that is commonly used in perfume making.  Both "Polianthes" and the related genus "Manfreda" are included in "Agave" by some sources.

Cucurbita digitata: Cucurbita digitata is a species of flowering plant in the squash family known by the common names fingerleaf gourd and bitter squash.  It is similar to "Cucurbita californica", "Cucurbita cordata", "Cucurbita cylindrata", and "Cucurbita palmata" and all these species hybridize readily.  These species form the only restricted xerophyte species group in the genus "Cucurbita".  Each member of this species group is native to the Southwestern United States and Northwestern Mexico where they are relatively uncommon.  Each group member is found in hot, arid regions with low rainfall.  They prefer soil that is loose, gravelly, and well-drained.  "C. digitata" is native to northern Baja California at higher elevations, northern Sonora, Mexico, southern Arizona, and southwestern New Mexico.  The juvenile leaves of "C. cylindrata", "C. cordata", "C. digitata", and "C. palmata" show a high degree of similarity, but their mature leaves are visibly different, as are their root structures.  "C. palmata" and "C. digitata" are sympatric, with "C. palmata" separating the ranges of "C. digitata" at the juncture of Baja California, California, and Arizona.  "C. digitata" fruits are clear green mottle that turns yellow at maturity, striped, and round.

Meriones (rodent): Meriones is a rodent genus that includes the gerbil most commonly kept as a pet, "Meriones unguiculatus".  The species of this genus are all called jirds, but also the species in the genus "Sekeetamys" is also known as "jird".  The distribution of "Meriones" ranges from northern Africa to Mongolia.  "Meriones" jirds tend to inhabit arid regions including clay desert, sandy desert, and steppe, but are also in slightly wetter regions, and are an agricultural pest.

Cucurbita cylindrata: Cucurbita cylindrata is a species of flowering plant in the squash family.  It is similar to "Cucurbita californica", "Cucurbita cordata", "Cucurbita digitata", and "Cucurbita palmata" and all these species hybridize readily.  These species form the only restricted xerophyte species group in the genus "Cucurbita".  Each member of this species group is native to the Southwestern United States and Northwestern Mexico where they are relatively uncommon.  Each group member is found in hot, arid regions with low rainfall.  They prefer soil that is loose, gravelly, and well-drained.  "C. cylindrata" is found only in the middle portion of Baja California, mostly in Baja California Sur.  Botanists Bemis and Whitaker suggest that "C. cordata" and "C. cylindrata" may be a case of sympatric speciation.  The juvenile leaves of "C. cylindrata", "C. cordata", "C. digitata", and "C. palmata" show a high degree of similarity, but their mature leaves are visibly different, as are their root structures.  "C. cylindrata" fruits are dark green, striped, and round.

Cucurbita palmata: Cucurbita palmata is a species of flowering plant in the squash family known by the common names coyote melon and coyote gourd.  It is similar to "Cucurbita californica", "Cucurbita cordata", "Cucurbita cylindrata", and "Cucurbita digitata" and all these species hybridize readily.  It was first identified by Sereno Watson in 1876.  These species form the only restricted xerophyte species group in the genus "Cucurbita".  Each member of this species group is native to the Southwestern United States and Northwestern Mexico where they are relatively uncommon.  Each group member is found in hot, arid regions with low rainfall.  They prefer soil that is loose, gravelly, and well-drained.  "C. palmata" is native to northeastern Baja California, southeastern California, and southwestern Arizona to a point near the Colorado River.  The juvenile leaves of "C. cylindrata", "C. cordata", "C. digitata", and "C. palmata" show a high degree of similarity, but their mature leaves are visibly different, as are their root structures.  "C. palmata" and "C. digitata" are sympatric, with "C. palmata" separating the ranges of "C. digitata" at the juncture of Baja California, California, and Arizona.  "C. palmata" fruits are diffuse green mottle that turns yellow at maturity, striped, and round.

Supporting paragraphs: Polianthes Agave
Answer: Agave