A Grammatical Dictionary of Botanical Latin

heteromallous (Eng.adj.): spreading or pointing in all directions (Jackson); “spreading or turning in different directions - used of leaves of various mosses; opp. to homomallous” (WIII) [> Gk. heteromallos, woolly, fr. hetero-, other, different + mallos lock of wool]; opp. homomallous, q.v.

NOTE: however, in ancient Greek ‘homomallos’ does not occur in Liddell & Scott. ‘Heteromallos,’ however does: meaning “woolly, shaggy on one side,” ‘heteros’ meaning ‘one or the other of two.’ It is in this sense that the bryophyte authors Bridel and Hedwig use heteromallus,-a,-um (adj.A) to refer to moss leaves that are secund or falcate-secund. The habit illustrations by Hedwig illustrate this meaning.

Bridel defines the following:

- [of the direction or manner of growth of the moss leaf) folia heteromalla tandem vel secunda ubi apice omnia ad unum latus convertuntur ut in Dicrano heteromallo (Brid.), finally, the leaves are hetermallous or secund when all of them at the apex are turned to one side as in Dicranum heteromallum.

Schwaegrichen (in Hedwig) defines the leaf direction (directio folii) of folia ‘heteromalla:’ “omnia apice versus unum latus curvata; all of the leaves at the apex curved toward one side.

Dicranum heteromallum (from the Greek adj. ἕτερος (heteros), different, various, and the noun μαλλός (mallós), a tuft of wool; together they form the Greek adj. ἑτερόμαλλος (heteromallos), meaning wooly or shaggy on only one side; inferring that the leaves of this species spread only on one side (falcate-secund), unlike their modern meaning (see homomallous).

- [Weisia heteromalla; moss] foliis e basi lata subulatis, rigidis heteromallis (Hedw.) with the leaves subulate from a broad base, rigid, heteromallous [note: the leaves are turned to one side].

- [Leskia attenuata; moss] foliis perichaetialibus, aetate quoque heteromallis, laxis (Hedw.) with the perichaetial leaves, even with age, heteromallous, lax.

- [Dicranum heteromallum; moss] foliis e membranacea basi subulatis secundis (Hedw.) with the leaves subulate from a membranaceous base, secund [i.e. turned to one side].

- [Dicranum scoparum] folia communia in summitate pauciora, subulato carinata, rigidiuscula, torsionem nullam recipientia, heteromalla (Hedw.), the primary leaves smaller at the summit, subulate-carinate, somewhat rigid, receiving no torsion [i.e. twisting], heteromallous.