 In this type of development, the cap is formed from hyphae at the top of the stem and subsequently expands by growth along the margins; the hymenium forms later beneath the cap in a direction away from the center.The mushrooms originate as minute fruit bodies (called "pins" due to their shape) from a yellow mycelium that forms a mat and tends to engulf pine needles.The pins, typically 1–2 mm in diameter, lengthen vertically until they are roughly three or four times longer than they are thick.