Question: What is a small genus of flowering plants in the family Cannabaceae, Sagina or Humulus ?

Context paragraphs:
Aphananthe: Aphananthe is a small genus of evergreen trees in the family Cannabaceae.  Around six species are recognised, found in Madagascar, South-east Asia, Mexico and Australia.  Leaves are alternate on the stem and toothed.  Flowers are unisexual, fruit form as drupes.  The generic name of "Aphananthe" refers to "insignificant flower"s. Species include "Aphananthe aspera" and "Aphananthe philippinensis".

Tripterocalyx: Tripterocalyx is a small genus of flowering plants in the four o'clock family.  It contains four species formerly included in the closely related genus "Abronia", the sand-verbenas.  These plants are native to North America, especially the dry desert southwest of the United States.  They bloom in heads of several colorful trumpet-shaped flowers.  Sandpuffs is a common name for plants in this genus.

Cannabaceae: Cannabaceae is a small family of flowering plants.  As now circumscribed, the family includes about 170 species grouped in about 11 genera, including "Cannabis" (hemp, marijuana), "Humulus" (hops) and "Celtis" (hackberries).  "Celtis" is by far the largest genus, containing about 100 species.

Cannabis sativa: Cannabis sativa is an annual herbaceous plant in the "Cannabis" genus.  It is a member of a small, but diverse family of flowering plants of the Cannabaceae family.  It has been cultivated throughout recorded history, used as a source of industrial fibre, seed oil, food, recreation, religious and spiritual moods and medicine.  Each part of the plant is harvested differently, depending on the purpose of its use.  The species was first classified by Carl Linnaeus in 1753.

Sagina: Sagina (like "Colobanthus" called "pearlworts") is a genus of 20–30 species of flowering plants in the pink or carnation family, Caryophyllaceae.  These are flowering herbs native to temperate regions of the Northern Hemisphere extending south to tropical mountain areas at high altitudes, reaching just south of the equator in Africa.  They are small annual or perennial herbaceous plants, growing to 5–15 cm.  The leaves are opposite, often in tight whorl-like clusters, simple linear, typically 5–20 mm long.  The flowers are solitary or in small cymes, with four or five green sepals and an equal number of white petals; the petal size relative to the sepal size is useful in species identification.  The fruit is a small capsule containing several seeds.

Colobanthus: Colobanthus is a large genus of small, cushion-like herbaceous plants, sometimes known as "pearlworts", a name they share with plants of the related genus "Sagina".  "C. quitensis" is the world's southernmost dicot, and one of only two original flowering plants of Antarctica.

Cannabis: Cannabis ( ) is a genus of flowering plant in the family Cannabaceae.  The number of species within the genus is disputed.  Three species may be recognized, "Cannabis sativa", "Cannabis indica" and "Cannabis ruderalis"; "C. ruderalis" may be included within "C. sativa"; or all three may be treated as subspecies of a single species, "C. sativa".  The genus is indigenous to central Asia and the Indian subcontinent.

Pericallis: Pericallis is a small genus of about 14 species of flowering plants in the family Asteraceae, native to the Canary Islands and Madeira.  The genus includes herbaceous plants and small subshrubs.  In the past, the genus was often included in either "Cineraria" or "Senecio.

Cystolith: Cystolith (Gr.  "cavity" and "stone") is a botanical term for the inorganic concretions, usually of calcium carbonate, formed in a cellulose matrix in special cells called lithocysts, generally in the leaf of plants of certain families, e.g. "Ficus elastica", the Indian rubber plant of the family Moraceae.  Plants in the family Urticaceae, also known as stinging nettles, also form leaf cystoliths, but only during their later flowering and seed setting stages.  Cannabis and other plants in the family Cannabaceae also produce leaf and flower cystoliths.

Humulus: Humulus, hop, is a small genus of flowering plants in the family Cannabaceae.  The hop is native to temperate regions of the Northern Hemisphere.  Hops are the female flowers (seed cones, strobiles) of the hop species "H. lupulus"; as a main flavor ingredient in beer, "H. lupulus" is widely cultivated for use by the brewing industry.

Supporting paragraphs: Humulus Sagina
Answer: Humulus