Is Guadua a Runner or a Clumper?

Guadua Rhizome Structure

A recent discussion we had was about the fact if Guadua is a clumping or a running bamboo type. "Officially" Guadua is classified as a clumper or "open clumper", however the reality is quite different;

"The rhizome structure and growth habit of Guadua reveals the limitations and occasional inadequacy of common terminology. Bamboo with pachymorph rhizome systems are commonly termed "clumping bamboos" because of their generally clumping habit, but some species of Guadua are hardly clumping. The long-necked rhizomes of certain species may extend some 20ft. (6m) or more before turning upwards into a new culm, easily outdistancing many "running" bamboos with leptomorph rhizome systems. Rather than "clumping" bamboo, Guadua bamboos are more properly characterized as having a pachymorph rhizome system and a diffuse habit - though even this rather understates the matter."