Hydnellum Peckii Fungus

In deposit, the spores appear brown. Viewing them with a light microscope reveals finer details of their structure: they are roughly spherical but end abruptly in a small point, their surfaces are covered with small, wart-like nodules, and their size is between 5.0–5.3 by 4.0–4.7 µm. The spores are in amyloid, meaning they do not absorb iodine when stained with Melzer's reagent.
Hydnellum peckii's cells (the hyphae) also present various characters useful for its characterization. The hyphae that form the cap are hyaline (translucent), smooth, thin-walled, and 3–4 µm thick. They collapse when dry, but may be readily revived with a weak (2%) solution of potassium hydroxide. Those in the cap form an intricate tangle with a tendency to run longitudinally. They are divided into cellular compartments (septa) and have clamp connections—short branches connecting one cell to the previous cell to allow passage of the products of nuclear division. The basidia, the spore-bearing cells in the hymenium, are club-shaped, four-spored, and measure 35–40 by 4.7–6 µm.
• Similar species
Hydnellum diabolus (the species epithet is given the neuter diabolum in some publications) has a very similar appearance, so much so that some consider it and H. peckii to be synonymous; H. diabolus is said to have a sweetish pungent odor that is lacking in H. peckii. The differences between the two species are amplified in mature specimens: H. diabolus has an irregularly thickened stem, while the stem of H. peckii is thickened by a "definite spongy layer". Additionally, old specimens of H. peckii have a smooth cap, while H. diabolus is tomentose. The related species H. pineticola also exudes pink droplets of liquid when young and moist. Commonly found growing under conifers in northeastern North America, H. pineticola tastes "unpleasant", but not acrid. Fruit bodies tend to grow singly, rather than in fused clusters, and, unlike H. peckii, they do not have bulbous stems.