Golden Spindles

The fruit bodies are cylindrical, bright yellow, growing up to 11 centimetres (4+1⁄4 in) tall in fasciculate (densely crowded) clusters of unbranched 'fingers' under 1 cm thick. Microscopically, the hyphae are hyaline, up to 12 μm in diameter, with clamp connections. The basidiospores are hyaline, smooth, globose to subglobose, 4.5 to 7.5 μm, with a large apiculus.

Similar species. In European grasslands, Clavulinopsis helvola, C. laeticolor, and C. luteoalba have similarly coloured, simple fruit bodies but are typically smaller and grow singly or sparsely clustered. The uncommon Clavaria amoenoides produces densely clustered fruit bodies but they are pale yellow and, microscopically, lack clamp connections. Ramariopsis kunzei bears a resemblance.

The species was initially described from England and is common throughout Europe. Its distribution outside Europe is uncertain because of confusion with similar, closely related species in the complex. Clavulinopsis fusiformis sensu lato has been reported from North America, Central and South America, and Asia, including Iran, China, Nepal, and Japan. The species typically occurs in large, dense clusters on the ground and is presumed to be saprotrophic. In Europe it generally occurs in agriculturally unimproved, short-sward grassland (pastures and lawns). Such waxcap grasslands are a declining and threatened habitat, but C. fusiformis is one of the commoner species and is not currently considered of conservation concern. Elsewhere, C. fusiformis sensu lato occurs in woodland. In China it is one of the dominant macrofungal species found in Fargesia spathacea-dominated community forest at an elevation of 2,600–3,500 metres (8,500–11,500 ft).

Fruit bodies are commonly collected and consumed in Nepal, where the fungus is known locally as Kesari chyau. Extracts from Japan have been found to contain an anti-B red blood cell agglutinin protein.