Hemizonia congesta ssp. tracyi - Holarrhena
- Hemizonia congesta ssp. tracyi
- Hemizonia congesta ssp. vernalis
- Hemizonia fasciculata
- Hemizonia fitchii
- Hemizonia floribunda
- Hemizonia kelloggii
- Hemizonia lobbii
- Hemizonia paniculata
- Henicodium
- Henicodium geniculatum
- Henriettea
- Henriettea fascicularis
- Henriettea macfadyenii
- Henriettea membranifolia
- Henriettea squamulosum
- Henrya
- Henrya insularis
- Hepatica
- Hepatica nobilis
- Hepatica nobilis var. acuta
- Hepatica nobilis var. obtusa
- Heppia
- Heppia adglutinata
- Heppia conchiloba
- Heppia lutosa
- Heracleum
- Heracleum mantegazzianum
- Heracleum maximum
- Heracleum sphondylium
- Heracleum sphondylium ssp. sibiricum
- Herbertia
- Herbertia lahue
- Herbertia lahue ssp. caerulea
- Herbertus
- Herbertus aduncus
- Herbertus aduncus ssp. aduncus
- Herbertus aduncus ssp. tenuis
- Herbertus hawaiiensis
- Herbertus himalayanus
- Herbertus sakuraii
