Question: Which genus was named after Saverio Manetti, Manettia or Rhododendron?

Context paragraphs:
List of Rhododendron species: This List of "Rhododendron" species includes species of the genus "Rhododendron", which is in the plant family Ericaceae.  Depending on the source, there are anywhere from 800 to over 1,100 wild species.  The vast majority of "Rhododendron" species are native to the eastern Himalaya and southeast Tibet, along with the islands of Java, Sumatra, Borneo, New Guinea, and the Philippines.  The rest are broadly spread throughout the northern hemisphere in relatively small isolated populations, including Japan, northwestern North America, the Appalachian, and the Caucasus Mountains.

Rhododendron subg. Rhododendron: Rhododendron" subgenus "Rhododendron is a subgenus of the genus "Rhododendron".  With around 400 species, it is the largest of the eight subgenera (more recently reduced to five) containing nearly half of all known species of "Rhododendron" and all of the lepidote (scales on the underside of the leaves) species.

Rhododendron: Rhododendron (from Ancient Greek ῥόδον "rhódon" "rose" and δένδρον "déndron" "tree") is a genus of 1,024 species of woody plants in the heath family (Ericaceae), either evergreen or deciduous, and found mainly in Asia, although it is also widespread throughout the highlands of the Appalachian Mountains of North America.  It is the national flower of Nepal.  Most species have brightly coloured flowers which bloom from late winter through to early summer.

Giovanni Targioni Tozzetti: Giovanni Targioni Tozzetti (Florence, 11 September 1712 - Florence, 7 January 1783) was an Italian naturalist.  He was supervisor of the Orto Botanico di Firenze in Florence succeeded by Saverio Manetti.  Apparently met Caso Umbria in the 1730s.

Saverio Manetti: Francesco Saverio Manetti also spelt Xaviero or Xaverio Manetti (Latinized as Franciscus Xaverius Manetti civis Florentinus) (12 November 1723 – 12 November 1785) was an Italian physician, botanist and ornithologist.  Among his works is the treatise on birds, "Ornithologia methodice digesta" or "Storia naturale degli uccelli" (1776).  The plant genus "Manettia" was named in his honour by Carolus Linnaeus.

Manettia: Manettia is a genus of flowering plants in the family Rubiaceae.  There are between 80 and 123 species.  They are distributed in the West Indies, Mexico, and Central and South America.  Most are vines.  The genus was named after Saverio Manetti.

Rhododendron ferrugineum: Rhododendron ferrugineum (sometimes called alpenrose, snow-rose, or rusty-leaved alpenrose) is an evergreen shrub that grows just above the tree line in the Alps, Pyrenees, Jura and northern Apennines, on acid soils.  It is the type species for the "Rhododendron" genus.  It may grow up to 1 m tall and produces clusters of pinkish-red, bell-shaped flowers throughout the summer.  The undersides of the leaves are covered in rust-brown spots, which give the species its scientific name.  This is in contrast to "Rhododendron hirsutum", which has no such brown colouring, has hairy edges to the leaves and grows over limestone.  Where the two species co-occur (usually on soils of intermediate pH), the hybrid "Rhododendron × intermedium" may occur; as its name suggests, it is intermediate in form between the two parental species.

Rhododendron subg. Choniastrum: Rhododendron" subg.  "Choniastrum is a subgenus of the genus "Rhododendron", originally a section of subgenus "Azaleastrum" it was elevated to subgenus rank after cladistic analysis revealed that together with "Rhododendron" it formed a major clade, distinct from other sections of "Azaleastrum".

Catawbiense hybrid: A catawbiense hybrid is a hybrid of the plant genus "Rhododendron", derived from crosses of American species "Rhododendron catawbiense" and "Rhododendron maximum" with European and Asian species "R. arboreum", "R. caucaseum" and "R. ponticum".

Rhododendron subsect. Ledum: Ledum was a genus in the family Ericaceae, including 8 species of evergreen shrubs native to cool temperate and subarctic regions of the Northern Hemisphere and commonly known as Labrador tea.  It is now recognised as a subsection of section Rhododendron, subgenus "Rhododendron", of the genus "Rhododendron".

Supporting paragraphs: Manettia Rhododendron
Answer: Manettia