Question: Is the plant Decumaria a genus of more species than the plant Pachycereus?

Context articles: Lophodermium
Hesperevax caulescens
Decumaria
Closterovirus
Weed
Pachycereus
Pachycereus marginatus
Sarcodes
× Pacherocactus
Pachycereus pecten-aboriginum

Lophodermium is a genus of fungi within the family Rhytismataceae.
 The genus contains 145 species and has a global distribution.
 Species of this genus are usually observed producing zone lines, conidiomata and ascomata on dead fallen leaves, but at least some are known to colonize living leaves.
 In many cases they then live inside the colonized leaf as a symptomless endobiont, where they are regarded as detritivores utilising dead plant matter.
 In a few cases they may kill all or part of the leaf prematurely, and there is a substantial literature dealing with those species as plant pathogens.
 The genus infects many different plant families but with a notable concentration in the family Pinaceae; many "Lophodermium" species are restricted to a single host genus (or even species), but some, particularly those infecting grasses, may infect several genera.
 Some are economically important plant pathogens, such as those that cause needlecast disease in European Black Pine, Scots Pine and Red Pine in forestry and christmas tree plantations.
 In these species, notably "L. pinastri" and "L. seditiosum", the fungal spores disperse and infect the pine needles in late summer, which turn brown by the following spring and then fall off.
Hesperevax caulescens is a small flowering plant in the daisy family.
 One common name for the plant is hogwallow starfish, as it is a somewhat flat, star-shaped plant which grows in mud.
 Another common name is dwarf dwarf-cudweed, as the three members of genus "Hesperevax" are known as dwarf-cudweeds and this species is smaller than the others.
 It may also be called involucrate evax, since its former Latin name was "Evax involucrata".
 This annual plant is a member of the vernal pool plant community in California, where it is possibly an endemic species, although its range might extend into Baja California.
 The hogwallow starfish radiates pale green spoon-shaped leaves in a basal rosette and extends a short erect stem.
 The flowers are less than two millimeters wide.
 This species grows along the outskirts of vernal pools in areas which have dried.
Decumaria, the woodvamps, is a genus of two species of flowering plants in the family Hydrangeaceae, one ("D. barbara") native to the southeastern United States, and the other ("D. sinensis") native to central China.
Closterovirus, also known as beet yellows viral group, is a genus of viruses, in the family Closteroviridae.
 Plants serve as natural hosts.
 There are currently 11 species in this genus.
 Diseases associated with this genus include: yellowing and necrosis, particularly affecting the phloem.
 This genus has a probably worldwide distribution and includes among other viral species the "Beet yellows virus" (the type species) and "Citrus tristeza virus", rather economically important plant diseases.
 At least some species require vectors such as aphids or mealybugs for their transmission from plant to plant.
A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place".
 Examples commonly are plants unwanted in human-controlled settings, such as farm fields, gardens, lawns, and parks. Taxonomically, the term "weed" has no botanical significance, because a plant that is a weed in one context is "not" a weed when growing in a situation where it "is" in fact wanted, and where one species of plant is a valuable crop plant, another species in the same genus might be a serious weed, such as a wild bramble growing among cultivated loganberries.
 Many plants that people widely regard as weeds also are intentionally grown in gardens and other cultivated settings, in which case they are sometimes called beneficial weeds.
 The term "weed" also is applied to any plant that grows or reproduces aggressively, or is invasive outside its native habitat.
 More broadly "weed" occasionally is applied pejoratively to species outside the plant kingdom, species that can survive in diverse environments and reproduce quickly; in this sense it has even been applied to humans.
Pachycereus is a genus of 9–12 species of large cacti native to Mexico and just into southern Arizona, United States.
 They form large shrubs or small trees up to 15 m or more tall, with stout stems up to 1 m in diameter.
Pachycereus marginatus is a species of plant in the Cactaceae family.
 (Also sometimes called "Mexican Fencepost Cactus".)
 It has columnar trunks that grow slowly to 12 feet (3.7m) and may reach 20 feet (6.1m) in height.
 Stems are 3 to 4 inches (9–10 cm) in diameter; ribs 5 to 7 inches (13–18 cm).
 Its central spine is about 3/8 inch (1 cm) in diameter with 5-9 radials and slightly yellowish in colour.
 Its cuttings are sometimes used to create a fences as it its spines are not a large or dangerous as some cacti.
Sarcodes is a monotypic genus of a north-west American, springtime, flowering plant in the heath family (Ericaceae), containing the single species Sarcodes sanguinea, commonly called the snow plant or snow flower.
 It is a parasitic plant that derives sustenance and nutrients from mycorrhizal fungi that attach to roots of trees.
 Lacking chlorophyll, it is unable to photosynthesize.
 Ectomycorrhizal (EM) symbioses involve a mutualism between a plant root and a fungus; the plant provides fixed carbon to the fungus and in return, the fungus provides mineral nutrients, water and protection from pathogens to the plant.
 The snow plant takes advantage of this mutualism by tapping into the network and stealing sugars from the photosynthetic partner by way of the fungus.
 This form of parasitism is known as mycoheterotrophy.
× "Pacherocactus is a genus of shrubby cactus, with only one known species, × "Pacherocactus orcuttii.
 It is a natural hybrid between "Pachycereus pringlei" and "Bergerocactus emoryi", discovered near Rosario, Baja California, Mexico.
 The plant's generic name is formed from those of its parents ("Pachycereus" and "Bergerocactus"); sometimes it can be found listed as "Pachycereus" × "Bergerocactus".
Pachycereus pecten-aboriginum (commonly known as hairbrush or Indian comb) is a columnar cactus plant native to Mexico.
 The can grow up to 15 meters high.
 The trunk of this species is 1.2 to 5 meters tall and the fruits are large and burlike.
 The species name, "pecten-aboriginum", is from the Latin, and means "native combs".
 It was inspired by the use of the fruits as hair combs.