Pyramidal or conical very long-lived evergreen trees up to 30 m tall and 200 cm diam., with irregular shoot growth, mostly pendulous branches, and strong epicormic shoots from layered stems. Trees frequently multi-leadered, malformed, spiral-grained, fluted, burled, and scarred, with spurred branch scars and persistent dead limbs. Bark on mature trees cracked or fissured, not shedding readily; outer surface of scales greybrown, with prominent irregular lenticels with black craters; undersurface brown, dull, ± fibrous, with weathered grey margins. Roots of mature trees plate-like, shallow, far-spreading, often with low rounded buttresses; mycorrnizal nodules simple or branched, epidermal hairs common. Layered plants forming dense stem and root entanglements; stem and root grafting prevalent. Cotyledons c. 3.5 × 1.5 mm, ±fleshy, arched, amphistomatic. Primary axis of seedlings and juveniles strongly recurved, becoming erect behind leaders. Leaves ± monomorphic; on adult branchlets c. 2.0 × 1.0 mm, rhomboid, scalelike, strongly keeled and bead-like, closely imbricate; decurrent at base, spirally arranged; amphistomatic; Florin ring indistinct or absent; marginal frill uneven and discontinuous; older leaves persistent, brown, semi-woody. Leaves on seedlings as above, but slightly longer and less appressed. No specialised resting buds formed. Plants unisexual, with inconstant males and females. Male cones solitary, terminal on foliage branchlets, sessile, with up to 20 sporophylls, each with 2 sporangia; pollen with a thick-walled finely granular cappa; sacci 2, small, each with a proximal tubercle at base. Female cones solitary, terminal on foliage branchlets, pendulous by curvature of cone axis, consisting of 5—8(—10) spoon-shaped spreading keeled fertile bracts separated by distinct internodes; ovules borne in a median position on adaxial surface of fertile bract, initially obliquely inclined towards cone axis and partially inverted, becoming erect at maturity but topographically inverted; seeds 5-8(-10), inverted, spaced; c. 2.2 × 2.0 mm, shortly oblong to squarish, dorsiventrally compressed, apex notched with a central prominent micropyle; seed coat brown, papery, loose, wrinkled when dry, turgid when wet, enclosing the ovoid compressed seed body; epimatium brown, papery, dry, erose, forming a split asymmetrical sheath around base of seed. Seeds maturing in c. 1 year from cone induction and germinating the following summer, buoyant and dispersed mainly by water.

Bushy shrubs or conical to oblong moderately longlived evergreen trees up to 20 m tall and 100 cm diam., with uniformly erect stems, branches, and branchlets, and strong sucker shoots from horizontal underground stems. Trees mostly single-leadered, strongly tapered, straight-grained, and clear of lower branches and defects, with prominent branch scars and abruptly upturned branch bases. Bark on mature trees forming thick irregular scales and vertical scale complexes, shedding slowly, leaving behind distinct hammer marks and wave patterns; outer surface of scales silvery-grey to grey-brown, with a veneer of weathered resin and small, rounded, stalk-like lenticels with brown craters; undersurface crimson, glistening with fresh resin, hard, with silvery-grey, weathered, often scalloped margins; shed bark forming a small raised mound of litter filled with fine roots at base of tree. Roots of mature trees oblique, peg-like, deeply descending; mycorrhizal nodules simple or in extensive branched complexes, epidermal hairs absent. Roots and underground stems of shrubs and sucker shoots forming dense red-brown entanglements; aerenchyma universally present in roots and underground stems under anaerobic conditions. Cotyledons c. 12.0 × 2.0 mm, submembranous, spreading horizontally, epistomatic. Primary axis of seedlings and juveniles erect. Leaves polymorphic; on adult branchlets c. 3.0 × 1.5 mm, rhomboid, scale-like, keeled, closely imbricate and whipcord-like, decurrent at base, spirally arranged, amphistomatic; Florin ring distinct though sunken; marginal frill distinct, continuous; older leaves very persistent, brown, semi-woody. Leaves on seedlings at first 5.0-10.0 mm long, subulate, bristle-like, spreading, decurrent at base, spirally arranged, amphistomatic; successive leaves initially longer, becoming progressively shorter, bilaterally flattened, falcate to triangular, graded in size, and secondarily 3-ranked and spiralled; ultimately scale-like, keeled, imbricate. No specialised resting buds formed. Plants unisexual, with inconstant males and females. Male cones solitary or rarely paired, terminal on foliage branchlets, sessile, with up to 12 sporophylls each with 2 sporangia; pollen with a thin-walled, finely tuberculate cappa and 2 prominent sacci. Female cones solitary, terminal on foliage branchlets, erect by curvature of cone axis, consisting of 2-5(-6) spoon-shaped ± spreading fertile bracts separated by short internodes, sometimes with a sterile cap; ovules borne in a median position on adaxial surface of fertile bract, initially obliquely inclined towards cone axis and partially inverted, becoming erect at maturity; bracts in distal region of cone sterile, reduced in size. Seeds 1-3(-5), erect, crowded if more than one; c. 3.5 × 2.5 mm, narrowly oblong, rounded in cross-section, with a small rounded recurved micropyle; seed coat purple to black with a glaucous sheen, finely striated; epimatium swollen, fleshy, greenish-yellow, ± smooth-margined, forming a split keeled asymmetrical sheath around base of seed. Seeds maturing in c. 1 year from cone induction, germinating in second summer following maturation, and dispersed mainly by birds.

Lagarostrobo Quinn, ut hie emendato, similis, strobilo femineo laxo e bracteis pluribus fertilibus cochlearibus composito, ovulis obliquis partim inversis, foliisque ad maturitatem imbricatis squamiformibus, differt autem fruticis arborisque habitu, caulibus ramis ramulisque erectis, vitae summa multo breviore, cotyledonibus linearibus epistomaticis, polymorphis plantularum plantarumque juvenalium foliis, stomatibus Florinii annulum prominentem etsi depressum exhibentibus, ligno resinifero, mycorrhizalibus radicis nodulis ab epidermalibus pilis destitutis, caulibus subterraneis, aerenchymate abundanti, pollinis grano tuberculato parietibus tenuibus sacculisque duobus prominentibus ornato, strobilo femineo erecto 2-6 bracteis fertilibus praedito, semine oblongo velo rotundato cum in sectione transversali visus est, epimatio tumido carnoso.