Families (As per The Plant List)

 
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

H

Haemodoraceae - 1 ( Anigozanthos flavescens)

Haloragaceae - 8 ( Laurembergia coccinea, Myriophyllum aquaticum, Myriophyllum indicum, Myriophyllum intermedium, Myriophyllum oliganthum, Myriophyllum siamense, Myriophyllum tetrandrum, Myriophyllum tuberculatum)

Hamamelidaceae - 4 ( Exbucklandia populnea, Laurembergia coccinea var. zeylanica, Liquidambar styraciflua, Loropetalum chinense)

Heliconiaceae - 4 ( Heliconia angusta, Heliconia bihai, Heliconia psittacorum, Heliconia rostrata)

Hernandiaceae - 1 ( Gyrocarpus americanus)

Hydatellaceae - 1 ( Trithuria konkanensis)

Hydrangeaceae - 5 ( Deutzia scabra, Deutzia staminea, Hydrangea anomala, Hydrangea macrophylla, Philadelphus coronarius)

Hydrocharitaceae - 23 ( Blyxa aubertii, Blyxa echinosperma, Blyxa octandra, Enhalus acoroides, Halophila beccarii, Halophila decipiens, Halophila ovalis, Halophila ovalis subsp. ramamurthiana, Halophila ovata, Halophila stipulacea, Hydrilla verticillata, Lagarosiphon alternifolia, Najas graminea, Najas indica, Najas malesiana, Najas marina, Najas minor, Nechamandra alternifolia, Ottelia alismoides, Thalassia hemprichii, Udora fernandesii, Vallisneria natans, Vallisneria spiralis)

Hydroleaceae - 2 ( Hydrolea zeylanica, Wigandia caracasana)

Hypericaceae - 11 ( Cratoxylum polyanthum, Hypericum androsaemum, Hypericum gaitii, Hypericum hookerianum, Hypericum humifusum, Hypericum japonicum, Hypericum monogynum, Hypericum mysurense, Hypericum patulum, Hypericum uralum, Hypericum wightianum)

Hypoxidaceae - 6 ( Curculigo capitulata, Curculigo maharashtrensis, Curculigo orchioides, Curculigo savantwadiensis, Curculigo trichocarpa, Hypoxis aurea)