Question: Are Ceratophyllum and Saguaro both plant genus? 

Context paragraphs:
Aldrovanda vesiculosa: Aldrovanda vesiculosa, commonly known as the waterwheel plant, is the sole extant species in the flowering plant genus "Aldrovanda" of the family Droseraceae.  The plant captures small aquatic invertebrates using traps similar to those of the Venus flytrap.  The traps are arranged in whorls around a central, free-floating stem, giving rise to the common name.  This is one of the few plant species capable of rapid movement.

Banksia sessilis: Banksia sessilis, commonly known as parrot bush, is a species of shrub or tree in the plant genus "Banksia" in the family Proteaceae.  It had been known as Dryandra sessilis until 2007, when the genus "Dryandra" was sunk into "Banksia".  The Noongar peoples know the plant as Budjan or Butyak.  Widespread throughout southwest Western Australia, it is found on sandy soils over laterite or limestone, often as an understorey plant in open forest, woodland or shrubland.  Encountered as a shrub or small tree up to 6 m in height, it has prickly dark green leaves and dome-shaped cream-yellow flowerheads.  Flowering from winter through to late spring, it provides a key source of food—both the nectar and the insects it attracts—for honeyeaters in the cooler months, and species diversity is reduced in areas where there is little or no parrot bush occurring.  Several species of honeyeater, some species of native bee, and the European honey bee seek out and consume the nectar, while the long-billed black cockatoo and Australian ringneck eat the seed.  The life cycle of "Banksia sessilis" is adapted to regular bushfires.  Killed by fire and regenerating by seed afterwards, each shrub generally produces many flowerheads and a massive amount of seed.  It can recolonise disturbed areas, and may grow in thickets.

Montsechia: Montsechia is an extinct genus of aquatic plants containing the species Montsechia vidalii, discovered in Spain.  "Montsechia vidalii" lived about 130 million years ago, during the Barremian age, and appears to be the earliest known flowering plant.  It has affinities with the modern genus "Ceratophyllum".

Hesperelaea: Hesperelaea is a plant genus with only one species, probably now extinct.  Hesperelaea palmeri was found only on Guadalupe Island, a small island in the Pacific Ocean, part of the Mexican state of Baja California, about 400 km southwest of Ensenada.  The last collection of the plant on the island was in 1875, so the species and the genus must now be presumed extinct.  An intensive search for the plant in 2000 was unsuccessful.

Ceratophyllum echinatum: Ceratophyllum echinatum, commonly called spineless hornwort, is an aquatic perennial plant of the genus Ceratophyllum.  It can be found in ponds and lakes.  It is principally an eastern North American species and the only species of its genus endemic to North America.

Saguaro: The saguaro ( , ] ) (Carnegiea gigantea) is an arborescent (tree-like) cactus species in the monotypic genus Carnegiea, which can grow to be over 40 ft tall.  It is native to the Sonoran Desert in Arizona, the Mexican State of Sonora, and the Whipple Mountains and Imperial County areas of California.  The saguaro blossom is the state wildflower of Arizona.  Its scientific name is given in honor of Andrew Carnegie.  In 1994, Saguaro National Park, near Tucson, Arizona, was designated to help protect this species and its habitat.

Ipheion: The flowering plant genus Ipheion (starflower, spring starflower) belongs to Allioideae subfamily of the Amaryllidaceae family.  The World Checklist of Selected Plant Families no longer recognize the genus, regarding it as a synonym of "Tristagma", although The Plant List accepts two species.

Falconeria: Falconeria is a monotypic plant genus in the family Euphorbiaceae, first described as a genus in 1839.  The genus is sometimes included within the genus "Sapium".  The sole species is Falconeria insignis.  The plant is found from India, Nepal, Bangladesh, and Sri Lanka to Indochina, China (Hainan, Sichuan, Yunnan), Thailand and Peninsular Malaysia.

Phyllanthus: Phyllanthus is the largest genus in the flowering plant family Phyllanthaceae.  Estimates of the number species in this genus vary widely, from 750 to 1200.  "Phyllanthus" has a remarkable diversity of growth forms including annual and perennial herbs, shrubs, climbers, floating aquatics, and pachycaulous succulents.  Some have flattened leaflike stems called cladodes.  It has a wide variety of floral morphologies and chromosome numbers and has one of the widest range of pollen types of any seed plant genus.

Ceratophyllum: Ceratophyllum is a cosmopolitan genus of flowering plants including four accepted species in 2016, commonly found in ponds, marshes, and quiet streams in tropical and in temperate regions.  It is the only genus in the family Ceratophyllaceae, itself the only family in the order Ceratophyllales.  They are usually called coontails or hornworts, although hornwort is also used for unrelated plants of the division Anthocerotophyta.

Supporting paragraphs: Ceratophyllum Saguaro
Answer: no