Suillus cavipes

Description

Suillus cavipes are found under tamarack (Larix laricina) throughout the range of the host tree. It is fairly unmistakable, featuring a dry, densely hairy brown cap, a beautifully yellow or greenish-yellow pore surface, and a stem that is almost always hollow in the base when mature. It is found in Europe and North America.

Although not generally rated highly, the Hollow Bolete is reported to be edible when thoroughly cooked. In Britain, this is a rare species and should not, therefore, be gathered for eating.

Common names: Hollow Bolete, The Hollow-Stalked Larch Suillus.

Mushroom Identification

1. Ecology

   Mycorrhizal with tamarack (Larix laricina); growing alone or gregariously; fall; northeastern and northern North America.

2. Cap

   3-10 cm; convex becoming broadly convex or flat, sometimes with a broad central bump; fairly dry; densely hairy with whitish to brownish hairs and fibers; yellowish-brown, reddish-brown, or brown; usually with white partial veil remnants on the margin.

3. Pore Surface

   Yellow or greenish-yellow; not bruising; pores angular and radially arranged (but not boletinoid), about 1 mm across; tubes to 5 mm deep.

4. Stem

   4-9 cm long; .5-1.5 cm thick; sometimes somewhat bulbous; yellow and smooth toward the apex, brownish and hairy below; sometimes with a fragile ring; hollow in the base.

5. Flesh

   White to yellowish; not staining on exposure.

6. Odor and Taste

   Not distinctive.

7. Chemical Reactions

   Cap surface red with ammonia; black with KOH; negative with iron salts. Flesh sea green with ammonia; negative or yellowish with KOH; negative with iron salts.

8. Spore Print

   Olive brown to brown.

9. Microscopic Features

   Spores 7-10 x 3.5-4 µ; smooth; subfusoid. Clamp connections present.

10. Similar Species

    Suillus grevillei has a bright yellow-orange cap and angular pores; it also occurs under larch.

History

This spectacular bolete was described in 1836 by the German mycologist Wilhelm Opatowski (1810 - 1838), who gave it the binomial scientific name Boletus cavipes.

It was not until 1964 that this unusual bolete was transferred to the genus Suillus by American mycologists Alexander Hanchett Smith (1904 - 1986) and Harry Delbert Thiers (1919 - 2000), whereupon this species acquired its currently accepted (by most but not all authorities) scientific name Suillus cavipes.

There are several synonyms of Suillus cavipes (Opat.) A.H. Sm. & Thiers including Boletus cavipes Opat., Paxillus porosus Berk., Boletinus cavipes (Opat.) Kalchbr., Boletinus cavipes var. aureus Rolland, and Boletinus cavipes f. aureus (Rolland) Singer.

The specific epithet cavipes means 'with a hollow stem', while the generic name Suillus comes from the Latin noun sus, meaning pig. Suillus, therefore, means 'of pigs' (swine) and is a reference to the greasy nature of the caps of all fungi in this genus.

Photo sources:

Photo 1 - Author: natureluvr01 (CC BY-SA 2.0)

Photo 2 - Author: Dezidor (CC BY 3.0)

Photo 3 - Author: natureluvr01 (CC BY-SA 2.0)

Photo 4 - Author: natureluvr01 (CC BY-SA 2.0)

Photo 5 - Author: Jason Hollinger (CC BY-SA 2.0)