A Grammatical Dictionary of Botanical Latin

Rhus (s.m.III) gen. sg. rhois, acc. sg. rhum (irregularly declined): the Sumach, Sumac or Shumac; Fernald (1950) indicated that this was the "old Greek and Latin name." In Greek the word is rhous, a bushy shrub, sumach. In Greek the word was both masc. and fem. and declined acc. sg. masc. as rhoon, dat. sg. fem. rhoOi, or gen. sg. rhou, dat. sg. rhoi; and not rhoidis as is rather routinely used in Botanical usage; see sumach;

Rhus, gen.sg. rhois (s.m.III) (irregular; apparently no plural)

            singular      
Nom.        rhus
Gen.        rhois [botany: rhoidis]
Dat.                [botany: rhoi or rhoidi]
Acc.        rhum [botany: rhoem; rhoidem]
Abl.                 [botany: rhoe or rhoide].

Rhus, Sumach. “The Greek name for one species, Rhus coriaria. Rhus typhina, stag-horn sumach, was also known to the early North American colonists as dyer’s sumach from the yellow dye which could be made from it. Anacarciaceae” (Stearn 1996).

NOTE: Rhus cotinus L., ‘cotinus’ is a noun in apposition; see cotinus,-i (s.m.II). The genus is of the feminine gender, the epithet is not.

Rhus L., Sumac, a feminine noun (R. typhina, R. glabra, R. copallina, R. aromatica.

It appears the (botanical) spelling of the taxonomic genus is Rhus (s.f.III), gen. sg. rhois or rhoidis, dat. sg. rhoi or rhoidi, acc. sg. rhoidem, , abl. sg. rhoide or rhoe.

- [RHUS Cominia.] Corolla, nectaria, numerus, germen didymum, stylus bifidus, COMINIAM a RHOE separare jubent (Swartz), the corolla, nectaria, the number, the double ovary, the bifid style direct separating COMINIA from RHUS.

- [Tribus I. Anacardieae. Folia pinnata v. 3-foliolata (in Rhoide interdum simplicia) (B&H), leaves pinnate or 3-foliolate (in Rhus sometimes simple [i.e. undivided].

- folia simplicia (vide 1, Rhoidem) (B&H), leaves simple (see number 1, Rhus).

- [Limonia] Rhoem refert (DeCandolle), it resembles Rhus.

- [Allophylus] OBS. Characteri hujus generis conveníunt flores Rhois Cominiae & [Rhus] Cobbe L. - vid. obs. in Rhoe.

APORETICA Forst., gen. huc etiam referri debet. Rhoi Cobbe simillima (Swartz).

[Allophyllus] [observation(s). The flowers of Rhus Cominia and Rhus Cobbe approach the character of this genus – see observation(s) in Rhus.

APORETICA Forst, this genus also ought to be brought back. It is most similar to Rhus.

- [Heeria; Anacardiaceae] includit species Rhoidis foliis simplicibus (B&H), [Heeria] includes species of Rhus with simple [i.e. undivided] leaves.

- [Limonia madagascariensis] Rhoem refert (DeCandolle), it resembles Rhus.

[fungus] Stilbum Rhoidis, B. & C. [on dead Rhus typhina].