Question: Which subgenus of the genus "Vaccinium" does this group of evergreen dwarf shrubs or trailing vines belong to, which Captain Henry Hall firstly successfully cultivated?

Context paragraphs:
Cranberry: Cranberries are a group of evergreen dwarf shrubs or trailing vines in the subgenus Oxycoccus of the genus "Vaccinium".  In Britain, cranberry may refer to the native species "Vaccinium oxycoccos", while in North America, cranberry may refer to "Vaccinium macrocarpon".  "Vaccinium oxycoccos" is cultivated in central and northern Europe, while "Vaccinium macrocarpon" is cultivated throughout the northern United States, Canada and Chile.  In some methods of classification, "Oxycoccus" is regarded as a genus in its own right.  They can be found in acidic bogs throughout the cooler regions of the northern hemisphere.

Henry Hall (American revolution): Captain Henry Hall was an American from Dennis, Massachusetts who fought in the American Revolutionary War, who later was the first to successfully cultivate cranberries.

Cranberry (disambiguation): The cranberry is a group of evergreen dwarf shrubs, bearing the fruit named after such.  It is also a color (Hex triplet #A61733), but the following may also refer to Cranberry:

Vaccinium macrocarpon: Vaccinium macrocarpon (also called large cranberry, American cranberry and bearberry) is a North American species of cranberry of the subgenus "Oxycoccus" and genus "Vaccinium".

Vaccinium: Vaccinium is a common and widespread genus of shrubs or dwarf shrubs in the heath family.  The fruits of many species are eaten by humans and some are of commercial importance, including the cranberry, blueberry, bilberry or whortleberry, lingonberry or cowberry, and huckleberry.  Like many other ericaceous plants, they are generally restricted to acidic soils.

Dryas (plant): Dryas is a genus of perennial cushion-forming evergreen dwarf shrubs in the family Rosaceae, native to the arctic and alpine regions of Europe, Asia and North America.  The genus is named after the Greek nymph Dryad.  The classification of "Dryas" within the Rosaceae has been unclear.  The genus was formerly placed in the subfamily Rosoideae, but is now placed in subfamily Dryadoideae.

Iris subbiflora: Iris subbiflora is a species in the genus "Iris", it is also in the subgenus of Iris.  It is a rhizomatous perennial, from Portugal and Spain in Europe.  It has evergreen broad leaves, forming dense clumps, it has dwarf stems in late spring, (between April and May), with 1 upright fragrant flower, in shades of purple, light red purple, grey-blue, blue-violet, or dark violet.  It has a beard which is generally blue, purple, or violet, but can fade to white, dull yellow, or dark yellow.  After being found in 1804, it was once a separate species until the late 70s, when it was reclassified as subspecies of "Iris lutescens", and renamed "Iris lutescens subsp.  subbiflora".  But in the 80s it was returned to an independent species but some authors and references still class the species as a synonym or subspecies.  It is cultivated as an ornamental plant in temperate regions.

Ulex minor: Ulex minor, Dwarf Furze or Dwarf Gorse is an evergreen dwarf shrub in the family Fabaceae, native to eastern England, France, Spain and Portugal.  It is restricted to lowland heathland habitats.

Sarcostemma: Sarcostemma is a genus of flowering plants in the dogbane family, Apocynaceae, first described as a genus in 1810.  The name is derived from the Greek words σαρκὸς ("sarkos"), meaning "flesh," and στέμμα ("stemma"), meaning "garland".  Members of the genus are known generally as climbing milkweeds or caustic bushes.  They are found across Africa and tropical Asia, in Australia, and in parts of North America.  These plants are perennial flowering shrubs with trailing vines or lianas.  They are often adapted to heat and/or desert conditions.  Some have few or no leaves and photosynthesize in the tissues of the green stems.  The soft stems are filled with a milky white latex that is poisonous and caustic in some species.  The flowers have a ring of thick tissue at the base which extends into hollow spherical appendages within the flower corolla.

Anogramma ascensionis: Anogramma ascensionis, the Ascension Island parsley fern, is a species of fern in the Pteridaceae family that is endemic to Ascension Island, a volcanic island in the South Atlantic Ocean.  It is one of eight putative species in the "Anogramma" genus.  It was thought to have become extinct due to habitat loss, until four plants were found on the island in 2010.  Over 60 specimens were then successfully cultivated at Royal Botanic Gardens, Kew and on Ascension Island.  It is now classified as Critically Endangered.

Supporting paragraphs: Henry Hall (American revolution) Cranberry
Answer: Oxycoccus