I have selected a few plant genera beginning with the letters D, E and F, along with any of their interesting species names, that I think could have potential use as a name choice.
Plant names:
A I B to C I D to F I G to J I K to M I N to O I P I R to S I T to V I W to Z
Dalea - Whereas Dahlia, named after Andreas Dahl, is meant to be pronounced DAH-lee-uh, Dalea, after English botanist Samuel Dale is DAY-lee-uh. Aurea "golden", Candida "white", Elata "elevated", Melantha "dark flower"and Verna "spring" are species.
Davallia - Fern plants named after the Swiss botanist Edmund Davall.
Decumaria - Most likely from the Latin decuma "tenth" as the seed pods are often in tens.
Deinanthe - From the Greek deinos which can mean "wonderful", "powerful" and "terrible" and anthos "flower".
Dianthus - The genus which includes carnations and sweet william. From the Greek dios "god, divine" and anthos "flower".
Dionaea - The Venus Flytrap. Dionaea, from Greek title "goddess", links directly to Venus/Aphrodite as a name she was sometimes referred to. In some versions of Greek mythology the goddess Dione is said to be Aphrodite's mother.
Diosma - From the Greek dios "divine" and osme "smell, aroma" referring to the plants' fragrant leaves.
Disa - The orchid flower, named after Queen Disa, a heroine in Swedish legend, possibly due to the net-like veins of the orchids' sepal which links to the saga in which Disa wears a fishing net. Species include Arida "dry", Aurata "gilded, golden", Montana "of the mountains", Rosea "rosy" and Venosa "veins".
Dracaena- Tropical foliage plants, from the Greek drakaina "female dragon", as the bright red resin is thought to resemble dragon's blood. It is commonly pronounced dra-SEE-na, although Drakaina has the hard 'k' sound. Interestingly, Drakaina is the professional name of a French model. Species include Amabilis "lovable", Draco "dragon" and Goldieana 'after Goldie".
Dryas - Derived from the Greek drus "oak" as the leaves of the plants resemble oak leaves. Several men in Greek mythology were called Dryas.
Elisena - Believed to be named after Elisa Bonaparte, sister of Napoleon. As a name, Elisena previously existed as a character in the 16th century Spanish tale Amadis de Gaula.
Elatine - An aquatic plant derived from the Greek elate "silver fir".
Eleocharis - Mesic plants derived from the Greek elos "marsh" and charis "grace". Bella "beautiful" is a species name.
Elodea - Aquatic plants native to North America from the Greek elodes "marshy".
Eranthis - From the Greek eiar "spring" and anthos "flowers" as they flower in early spring.
Eucharis - Closely resembling daffodils. From the Greek eucharistos "pleasing", ultimately from eu "good" and charis "grace". Candida "white" is a species name.
Fagus - The genus of Beech. Derived from the Latin word for a Beech tree. The name appears as a Romano-Gallic god of beech trees. Lucida "shining" is a species.
Franciscea - Named after Francis, Emperor of Austria, who was a patron of botany.
Freesia - Named for German physician Dr F.H.T. Freese.
Fuchsia - Named after German botanist Leonard Fuchs. The colour fuschia is derived from the flower and is synonymous with magenta.
Beyond Dionaea, Disa and Dryas, some names of genera that were already (non-nature) first names include: Danae, Daphne, Emilia, Erica, Eulalia, Fabiana and Felicia.