A Grammatical Dictionary of Botanical Latin

interdum (adv.): “sometimes, occasionally, now and then; for some time [i.e. per aliquod tempus]; meanwhile, in the meantime [= interea, interim]” (Lewis & Short); = nonnumquam (adv.), q.v., ‘sometimesn’;now and then’ cf. subinde (adv.), at more or less frequent intervals of time, from time to time, now and then; at intervals of space; cf. plerumque (adv.), for the most part, very frequently, commonly; cf. saepe (adv.), often, frequently;

- flores minuti, albi, primum subcorymbosi, demum racemosi; rachide interdum spinescente (B&H), the flowers minute, white, st first nearly corymbose, thereafter racemose; with the rachis now and then growing spinescent.

- radice nititur satis tenui & simplici; caulem tollens interdum simplicem, interdum ramosum (Ray), with a [shining] root, quite thin and simple [i.e. unbranched]; raising up sometimes an unbranched stem, sometimes a branched one.

- chloroplasti plerumque lumen cellulare cingentes vel interdum ab extremo altero leviter retracti, chloroplasts usually surrounding the cell lumen but sometimes lightly retracted from one (of two) ends.

- apicibus solum interdum deciduis, with the apices only sometimes deciduous.

- priori valde aff. et cum ea interdum in hortis confusa (DeCandolle), strongly [i.e. closely] related to the prior [sc. species] and with this sometimes confused in gardens.

- herbae, foliis alternis interdum dissectis nec compositis (B&H), herbs, with the leaves alternate, occasionally dissected, not compound.

- stipulae saepe adsunt et interdum spinescent (B&H), the stipules often present and sometimes somewhat spiny.

- Ovarium integrum, erectum, stipiti brevi interdum incrassato v. in discum dilatato impositum (B&H); ovary entire, erect, with a short stipe sometimes thickened or situated on a broadened disk.

- [algae] tubercula minuta, (capitulo aciculi [sic] minora), marginalia, plerumque opposita, rarius sparsa, interdum bina terminalia (Agardh), the tubercles tiny, (smaller than the capitulum of the aciculus), marginal, usually opposite, more rarely scattered, sometimes terminal, in pair(s).