Question: Which plant has more species, Heptacodium or Darwinia?

Context paragraphs:
Heptacodium: Heptacodium is a genus of plant in family Caprifoliaceae, comprising just the one species found in China:

Darwinia (plant): Darwinia, sometimes commonly known as mountain bells or simply bells, is a genus of about 70 species of evergreen shrubs in the family Myrtaceae, endemic to southeastern and southwestern Australia.  The majority are native to southern Western Australia, but a few species occur in South Australia, New South Wales and Victoria.  The genus was named in honour of Erasmus Darwin, grandfather of Charles Darwin by Edward Rudge in 1816.  Most darwinias grow to a height of between 0.2 and 3 m and many are prostrate shrubs.  Most have small, simple leaves and the flowers are often grouped together, each flower with five red, white or greenish petals and ten stamens.  In many species, the flowers are surrounded by large, colourful bracts, giving rise to their common names.

Darwinia glaucophylla: Darwinia glaucophylla is a plant species that is endemic to the Gosford area in the Australian state of New South Wales.  The species is listed as "threatened" under the NSW Threatened Species Conservation Act 1995.

Heptacodium miconioides: Heptacodium miconioides, commonly known as the Seven Sons plant, is a member of the Caprifoliaceae family, a cousin of the Honeysuckle, and sole member of the genus "Heptacodium".  Endemic to China, this species was discovered in 1907 in Hubei province in central China by Ernest Wilson whilst collecting on behalf of the Arnold Arboretum.  Considered rare even at that time, only nine populations are known to remain in the wild, all of them in Anhui and Zhejiang provinces and threatened by habitat loss.  The species is now under second-class national protection in China.  However, the Sino-American Botanical Expedition of 1980 collected viable seeds and sent them to the Arnold Arboretum where it was found to be readily cultivated.  The plant is now widely grown as an ornamental around the world.

Darwinia procera: Darwinia procera is a plant in the myrtle family Myrtaceae and is endemic to a small area in New South Wales.  It is a shrub with laterally compressed leaves, so that they are thicker than wide.  The flowers are reddish-purple and arranged in groups of four near the ends of the branches.  Although rare in nature, this species is often grown by native plant enthusiasts.

Darwinia biflora: Darwinia biflora is a plant in the myrtle family Myrtaceae and is endemic to New South Wales.  It is an erect, often straggly shrub with flattened, glabrous leaves, and flowers which are arranged in pairs.  The flowers are greenish in colour but each is surrounded by two purple-red bracteoles and have a long yellow-green style projecting out of the flower tube.  The species only occurs in the Sydney region in a few places where shale-capped ridges intergrade with Hawkesbury sandstone.

Darwinia oxylepis: Darwinia oxylepis, commonly known as Gillham's bell, is a plant in the myrtle family Myrtaceae.  It grows as an dense, upright shrub 1.0 - 1.5 metres (3 – 4.5 ft) high and produces large numbers of red inflorescences prominently displayed on the ends of the branchlets in spring.  It is one of a group of Darwinias including "D. leiostyla", "D. macrostegia", "D. meeboldii", "D. collina" and "D. squarrosa" collectively known as mountain bells.  The species is found in only a few seasonally moist gullies near the lower slopes of the Stirling Range National Park and nearby Porongurup National Park and is therefore classified as endangered.

Darwinia capitellata: Darwinia capitellata is a plant in the myrtle family Myrtaceae and is endemic to the south-west of Western Australia.  It is a bushy, many-branched shrub, very similar to "Darwinia diosmoides" but differs in the arrangement of its flowers, its more branched habit, prominent oil glands on the younger stems and its thinner, paper-like bracteoles.  It was first discovered as a separate species when specimens of it were found to have a larger chromosome number than specimens of "D. diosmoides".

Darwinia collina: Darwinia collina, commonly known as the yellow mountain bell, is a plant in the myrtle family Myrtaceae.  It grows as an erect shrub 0.3-1.2 m high with crowded elliptical leaves and bright yellow flower-like inflorescences.  It is endemic to a few small areas in the Stirling Range National Park, Western Australia and as a result is classified as an endangered species.

Darwinia citriodora: Darwinia citriodora, commonly known as lemon-scented darwinia or lemon scented myrtle, is a plant in the myrtle family Myrtaceae and is endemic to the south-west of Western Australia.  It is a shrub with oblong to lance-shaped leaves and red, yellow and orange flowers over an extended period.  It is a hardy plant in well-drained soil, is often cultivated and used as a rootstock for less hardy species.

Supporting paragraphs: Heptacodium Darwinia (plant)
Answer: Darwinia