North Island: Auckland, Mill Bay, 29.vi.81, coll. EH, no. 43690 (TENN); WKR, vic. Forestry Headquarters, 21.vi.81, coll. RHP, no. 42410 (holotype, PDD; isotype, TENN); WR, 29.iv.83, coll. RHP, no. 44079,44080 (TENN); Auckland, Mill Bay, 5.v.83, coll. RHP, no. 44083 (TENN). South Island: ATNP, Coast track, 16.v.82, coll. GS, no. 43554 (TENN).

Fruit bodies up to 80 x 6 mm, simple clubs occurring singly or in small groups of up to three individuals, occasionally connate or branched once, cylindrical to fusiform. Club white, buff ("pale cinnamon-pink") to pale dull yellow ("cartridge-buff"), opaque, often somewhat longitudinally rugulose or fluted to sublacunose, expanding somewhat upward; apex rounded. Stipe concolourous with club, tapering slightly downward, appearing shiny-silky, inserted with a very small whitish mycelial patch. Taste and odour negligible.
Macrochemical reaction: FCL = negative.
Tramal hyphae hardly inflated, strictly parallel, thin-walled, hyaline, clampless; secondary septa rare. Subhymenium well-developed, pseudoparenchymatous. Basidia 40-50 x 8-10 µm, clavate, guttulate when young, bifurcate to clamped (obscurely so in mature hymenium), persistent after spore discharge; sterigmata 4, stout, curved, ascending; contents homogeneous to minutely multiguttulate; cystidia (or basidioles) broadly clavate, apically thick-walled, hyaline, non-emergent.
Spores 6.1-7.9 x 4-5.4 µm (E = 1.21-1.64; E^m = 1.45; L^m = 6.94 µm), angular-ellipsoid, lobed to tuberculate-spiny, often with the protuberances only on the abaxial surface; contents opalescent when fresh, homogeneous to 1-2 guttulate when dry; wall thin, easily collapsed on drying; hilar appendix prominent.

Receptacula ad 80 x 6 mm, simplicia, gregaria, alba vel cremea. Hyphis efibulatis; basidiis fibulatis. Sporis ellipsoideis, angularibus, tuberculo-echinulatis, ut in oratione infra.

The spores, although different in wall thickness and persistence, are very similar to those of Ramariopsis helvola (Pers.) Pet. in outline only. Clavaria californica shares general fruitbody colour, bifurcate basidia, ellipsoid and ornamented spores but spore ornamentation is different.
The spores of Clavaria tuberculospora are thin-walled and collapse on drying, so turgid spores are scarce in mounts. Of all the collections, TENN no. 42410 is by far the best, with spores of normal shape. Some spores seem to be angular, others angular-tuberculate, and a few seem to have these lobes attenuated into blunt spines. Such variation and shape have not been reported in the genus before.
Basidia and "cystidia" are uniformly clamped or bifurcate in young hymenia, but many are not so in thickened hymenia. This may be less common than observed, for basidial bases are extremely difficult to observe in thickened hymenium, but several individuals were seen to be simple-septate.
The structures described as cystidia are inconspicuous, often appearing empty, and are broader than basidia, although no longer. Moreover, they are commonly transversely septate in the lower half, and the apical wall is usually thickened (up to 0.7 µm thick). Whether they are true cystidia or aberrant basidia cannot be ascertained. If correctly interpreted, they are very common, outnumbering mature basidia.