Foray at Black Hill Regional Park (Boyds, MD)

Today I went to a foray organized by MAW at Black Hill Regional Park (thanks Mitch!). Perhaps because it was in Boyds and because the weather today was a little bit on the hot side (maxima of 38C), not many people showed up. On the other hand, maybe it was that fact that it had not rained much over the last few days, that we've been having almost daily temperatures on the 32-40C (90-100) range or it was just the disappointing results of the last foray at Lake Bernard Frank that dissuaded most people to come. In any case, it was unfortunate for those that missed it, and to my surprise, this time we found a very large variety (and I really mean large) of amanitas and boletes. Most of them were starting becoming infested by insects, but we had the chance of seeing mushrooms on all developmental stages. Indeed, I would say that this foray was a paradise for boletes afficionados, with boletes popping up everywhere (some the size of my cap). Some of the mushrooms that we think we could identify were Telephora vialis (Vase Telephore), Laetiporus cincinnatus (Chicken of the Woods), Boletus vermiculosoides, Scleroderma citrinum (Pigskin Poison Puffball), Tylopilus plumbeoviolaceous (Violet-gray Bolete), Boletus pallidus (Pale Bolete), Boletus carminiporus, Amanita flacoconia, Amanita brunnescens (Cleft-foor Amanita), Amanita citrina (Citron Amanita), Amanita flavorubescens (Yellow Blusher), Cantharellus lateritius (Smooth Chanterelles), Amanita virosa (Destroying Angel) and Stereum ostrea (False Turkey-tail). We also found some Lepiotas and russulas and some old polypores (as usual). Because bolete identification is challenging and because I am a complete newbie to it, I brought a few specimens home to try my best on them. The specimen I am going to describe was particularly interesting because it follows the general rule of bolete edibility (i.e. does not stain blue, does not have red pore surface and does not taste bitter).

Date: 07/23/2011
Location: Black Hill Regional Park, Boyds, MD
Habitat: Growing on soil, two specimens near each other, on oak forest

Note the bright yellow hymenium
that does not stain.

Measurements
Pileus diameter - 56 mm
Pileus height - 15 mm
Stipe length - 61 mm
Stipe diameter at apex - 12 mm
Stipe diameter at middle - 12 mm
Stipe diamter at base - 14 mm tapering until 8 mm at the tip

Description
Pileus - convex, smooth, dull, pale brown/beige, flesh is pale yellow, does not bruise when cut, odor is non-distinctive, taste is mild, perhaps slightly acidic.
Hymenium - bright yellow, does not stain, tubes are 3 mm long, pores are angular and approximately 0.6mm in diameter.
Stipe - central, nearly equal somewhat clavate, solid, light yellow, cuticle is glabrous and with shallow ribs, yellowish near the apex and brown near the base with a white tip at the far bottom, not reticulated, without ring or partial veil.

Comments

Note the clavate stipe with shallow
ribs.

Most probably this mushroom is a Boletus innixus. Other look alikes are B. flaviporus and B. auriporus (which by the way was our first guess). B. innixus has a non-distinctive flavor and a short (3-6 cm long, 1-1.6 cm thick at apex and up to 2.5 cm at base) club shaped stout stipe (the measurements of my specimen could perhaps follow under this definition) while B. flaviporus is supposed to have an acidic flavor and to have a long (1-3 cm long), thick (1-3 cm) and nearly equal or tapered in either direction stipe (my specimen was nearly equal). Maybe more important, B. flaviporus is supposed to occur only in California and Oregon, while B. innixus is supposed to occur in the east coast. B. auriporus has appressed microfibrils on pileus and it stains brick-red (slowly) when bruised while B. flaviporus is subtomentose to glabrous and does not stain when bruised. The distinction between B. flaviporus and B. innixus is not obvious to me and it suggests that they may be the same mushroom (if anyone know of molecular evidence or any other type of morphological evidence that can clearly distinguish these two mushrooms, please enlighten me about it!). In any case, all three species are edible.

References
North American Boletes: A Color Guide to the Fleshy Pored Mushrooms, pages 95, 112 and 123