1 syllable:
&burn, bearn, bern, berne, birne, bkorn, burn, burn-e, burne, byrne, cern, cerne, chern, cherne, churn, cleburne, dearn, dern, derne, dirne, durn, earn, erne, fearn, fern, ferne, gerne, hearn, hearne, hern, herne, hirn, hurn, j-turn, journ, kearn, kern, kerne, kirn, learn, morne, quern, scern, shern, spurn, stearn, stearne, stern, sterne, stirn, sturn, terne, thurn, turn, turne, urn, vern, verne, yearn, yerne, zurn

2 syllables:
adjourn, ahearn, ahern, aherne, alpern, alterne, amburn, asperne, attorn, ball fern, bead fern, beech fern, bradburn, brightburn, bruce dern, camburn, chain fern, cisturn, clayburn, cockburn, cogburn, concern, concern', crepe fern, crewkerne, decern, deer fern, deturn, discern, disturn, ditch fern, diurne, dornbirn, downturn, eastburn, edirne, etern, eterne, excern, extern, externe, fairburn, fan fern, felt fern, film fern, fishburn, flip-turn, footworn, freeburn, gehirn, glade fern, glassburn, glenburn, gold fern, good turn, grape fern, grass fern, half-turn, hand fern, hardfern, hard fern, heartburn, hebburn, iceburn, ill turn, imgburn, interne, inturn, in turn, kick turn, kinburn, king fern, lace fern, lampern, lantirn, lavern, laverne, lean-burn, lip fern, lisburn, luverne, male fern, marshburn, marsh fern, mashburn, mcgurn, mckern, milburn, minturn, misturn, mowburn, new-bern, newburn, new bern, nocturn, o'beirne, o'byrne, o'hearn, o'hern, oak fern, obyrne, ohearn, ohern, osburn, outburn, pangburn, pine fern, rasp fern, re-turn, reburn, redburn, redfern, rejourn, return, rootcern, rope burn, sauterne, scale fern, secern, seed fern, self-bern, shield fern, sideburn, snake fern, springburn, stem turn, still-burn, stjerne, strap fern, sunburn, sweet fern, sword fern, tea urn, tongue fern, tree fern, u-turn, unturn, unworn, upturn, wall fern, washburne, whisk fern, winburn, windburn, wood-fern, woodburn, woodfern, wood fern

3 syllables:
about-turn, about turn, altbayern, ampere-turn, arterburn, bamboo fern, basket fern, berry fern, bird's nest fern, black tree fern, bladder fern, boston fern, boulder fern, bristle fern, brittle fern, broad beech fern, butter churn, button fern, christmas fern, cisternerne, climbing fern, clover fern, coffee fern, coffee urn, counterturn, creeping fern, dagger fern, day return, devil's urn, elkhorn fern, erwidern, false return, floating fern, fragile fern, giant fern, glory fern, golden fern, hartford fern, holly fern, in return, jersey fern, joint return, kidney fern, lady fern, leather fern, limestone fern, long beech fern, meadow fern, mountain fern, new york fern, ostrich fern, otterburn, overburn, overturn, overworn, readjourn, ribbon fern, royal fern, sago fern, scented fern, self-concern, sempiterne, serpent fern, silver fern, slash-and-burn, smooth lip fern, soft shield fern, soft tree fern, spider fern, taciturn, tax return, toothed sword fern, unconcern, underturn, walking fern, water fern, winter fern, winter urn, with concern

4 syllables:
annual fern, aquatic fern, banking concern, braun's holly fern, buckler fern, business concern, carriage return, cigarette burn, cinnamon fern, curly grass fern, earthly concern, flowering fern, fragrant cliff fern, fragrant shield fern, fragrant wood fern, gabriel byrne, hairy lip fern, licorice fern, mosquito fern, mountain male fern, narrow beech fern, nebraska fern, northern beech fern, northern oak fern, overconcern, pay as you earn, potato fern, prickly shield fern, printing concern, rattlesnake fern, sale-or-return, sensitive fern, silver tree fern, southern beech fern, umbrella fern, without concern, wooly lip fern, worldly concern

5 syllables:
alpine lady fern, amended return, asparagus fern, brittle bladder fern, california fern, climbing bird's nest fern, evergreen wood fern, florida strap fern, income tax return, interrupted fern, leathery grape fern, marginal wood fern, massachusetts fern, mountain bladder fern, mountain parsley fern, northern holly fern, oleander fern, packaging concern, point of no return, resurrection fern, skeleton fork fern, southwestern lip fern, virginia chain fern, western holly fern

6 syllables:
alabama lip fern, american wall fern, carolina pond fern, exponential return, giant scrambling fern, indian button fern, information return, mecklenburg-vorpommern

7 syllables:
american parsley fern, estimated tax return, european parsley fern

8 syllables:
canary island hare's foot fern, central american strap fern

2 syllables:
postern