A cactus (plural: "cacti", "cactuses", or "cactus") is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales.
 The word "cactus" derives, through Latin, from the Ancient Greek κάκτος , "kaktos", a name originally used by Theophrastus for a spiny plant whose identity is not certain.
 Cacti occur in a wide range of shapes and sizes.
 Most cacti live in habitats subject to at least some drought.
 Many live in extremely dry environments, even being found in the Atacama Desert, one of the driest places on earth.
 Cacti show many adaptations to conserve water.
 Almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water.
 Unlike many other succulents, the stem is the only part of most cacti where this vital process takes place.
 Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves.
 As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade.
 In the absence of leaves, enlarged stems carry out photosynthesis.
 Cacti are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north—except for "Rhipsalis baccifera", which also grows in Africa and Sri Lanka.
Jasminocereus (meaning "jasmine-like cereus", referring to the flowers) is a genus of cacti with only one species, Jasminocereus thouarsii, endemic to the Galápagos Islands, territorially a part of Ecuador.
 In English it is often called the candelabra cactus (a name used for other cacti with a similar appearance).
 At maturity it has a branched, treelike habit, and may be up to tall.
 The stems are made up of individual sections with constrictions between them.
 Its creamy white to greenish flowers open at night and are followed by greenish to reddish fruits.
Night-blooming cereus is the common name referring to a large number of flowering ceroid cacti that bloom at night.
 The flowers are short lived, and some of these species, such as "Selenicereus grandiflorus", bloom only once a year, for a single night.
 Other names for one or more cacti with this habit are princess of the night, Honolulu queen (for "Hylocereus undatus"), Christ in the Manger, Dama de Noche and queen of the night (which is also used for an unrelated plant species).
Cereus is a genus of cacti (family Cactaceae) including around 33 species of large columnar cacti from South America.
 The name is derived from Greek (κηρός) and Latin words meaning "wax" or "torch".
 The genus "Cereus" was one of the first cactus genera to be described; the circumscription varies depending on the authority.
 The term "cereus" is also sometimes used for a ceroid cactus, any cactus with a very elongated body, including columnar growth cacti and epiphytic cacti.
Cereus chalybaeus is a cactus from the genus "Cereus", a genus consisting of about 25 species of tree-like cacti.
 "Cereus chalybaeus" is a columnar cactus with 5-6 ribbs.
 It is few-branched and often purple tinged.
 It has spines that at first are red, but with age turn black.
 In summer it bears funnel-shaped flowers, which can be up to 8 inches long.
 The inner petals are white and the outer petals are either purple or red.
 "Cereus chalybaeus" can grow up to 10 feet tall and can be up to 28 inches in diameter.
 This plant is native in hardiness zones 13-15 (Northern Argentina and Uruguay).
Limnanthes, the type genus of the family Limnanthaceae, consists of annual herbaceous plants commonly known as the meadowfoams.
 The seven species are all native to coastal and adjoining regions (inland valleys, foothills and mountains) of western North America, where they typically grow in marshy habitats, such as the margins of vernal pools.
 Some are endemic to California
Richard Ernest Kunze (b. in Altenburg, Germany, 7 April 1838; d. 1919) was a physician.
 He came to the United States in 1854, and was graduated at the Eclectic Medical College of New York in 1868, subsequently becoming a member of the board of trustees of this institution, was president of the New York Therapeutical Association in 1880, introduced to the medical profession various drugs derived from cacti, and added greatly to the previous knowledge of medical botany.
 He published a series of monographs on "Cactus" (Albany, 1875); "Cereus Grandiflorus and Cereus bonplandi" (1876); "Cereus triangularis and Phyllocactus grandis" (1876); "Cardinal Points in the Study of Medical Botany" (New York, 1881); and "The Germination and Vitality of Seeds" (1881).
Limnanthes striata was formerly a species of meadowfoam known by the common name foothill meadowfoam.
 It has recently been subsumed into the species "Limnanthes douglasii" in both the Jepson Manual and the Flora of North America.
 This plant is endemic to California, where it is known from the Sierra Nevada foothills and the southern Klamath Mountains.
 It grows in wet, grassy habitat, carpeting the edges of vernal pools and ephemeral creeks.
Epiphyllum oxypetalum (Dutchman's pipe cactus or queen of the night ) is a species of cactus and one of the most cultivated species in the genus.
 "E. oxypetalum" blooms rarely and only at night, and its flowers wilt before dawn.
 Though it is sometimes referred to as a nightblooming cereus, it is not closely related to any of the species in the tribe Cereeae, such as "Selenicereus", that are more commonly known as nightblooming cereus.
 All Cereus species bloom at night and are terrestrial plants; all "Epiphyllum" species are usually epiphytic.
The term ceroid cactus (or sometimes just cereus) is used to describe any of the species of cacti with very elongated bodies, including columnar growth cacti and epiphytic cacti.

Question: Which cacti has more species, Cereus or Limnanthes?
Answer: Cereus