E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
{See also Morels Table.} Features include conic cap with ridges and vertically oriented pits, attached to stipe with small trough at lower margin, pale colors (but the ridges darken when old), stem that is not conspicuously lacunose, and growth under hardwoods in the lowlands but under conifers at medium to high elevations. Kuo called this the "western blond", and he in turn linked it to the Pilz(2) description of the "mountain blond" (PS-E), but changed the English name to reflect that it also occurs in the lowlands. Later Kuo(2) described Morchella frustrata, saying that it 'is likely the same as the morel informally designated the "mountain blond morel"' in Pilz(2). Descriptions of these two concepts are used below. Richard(1) has synonymized Morchella frustrata with Morchella tridentina.

Collections of Morchella frustrata were examined from CA and OR (Kuo(6)). The species is also found in Europe, including France, Italy, and Spain, (Richard), assuming that the synonymy is correct. M. Beug, pers. comm., has found M. tridentina throughout WA under both conifers and Quercus garryana (Oregon White Oak). He also identified a J. Riley photograph from BC on the E-Flora BC website as representing M. tridentina.

Cap:
2.5-4cm wide, 4-6cm high, (fruitbody 6-9cm high), conic, with 16-22 primary vertical ridges and a few shorter secondary ridges, with frequent sunken transecting horizontal ridges, sinus [trough] at the attachment to stem about 0.2-0.4cm deep and 0.2-0.4cm wide, ridges slightly flattened when young but often becoming sharp or eroded when old, pits primarily elongated vertically; ridges "pale yellowish to nearly whitish when young", becoming pale tan when mature, pits "dull grayish to pale yellowish or nearly whitish when young, becoming pale tan to pale pinkish tan"; ridges and pits bald, (Kuo(6)), cap "columnar to narrowly obtusely conic when young, variously expanding with maturity but typically remaining relatively narrow in relation to height"; ribs when young pale grayish tan, when old ivory to pale tan and then often with rusty ocher stains, pits when young are light smoky gray, when old near straw color or the color of a manila folder; ribs are essentially bald when young, when old becoming dry and waxy; edges typically remain intact and sterile, (Pilz)

Flesh:
whitish, 0.1-0.2cm thick in hollow cap, sometimes slightly chambered near stem base, (Kuo(6))

Underside:
trough between cap and stem about 0.2-0.4cm wide and 0.2-0.4cm wide; sterile inner surface whitish, pubescent, (Kuo(6))

Stem:
2-4cm x 1-2.5cm, more or less equal or sometimes basally subclavate [somewhat club-shaped]; whitish; bald "or finely mealy with whitish granules", (Kuo(6)), ivory to cream, "sometimes with rust-colored or amber discolorations"; bald, (Pilz)

Microscopic:
spores 20-29 x 14-19 um, elliptic, smooth, contents homogeneous; asci 8-spored, 225-300 x 15-25 um, cylindric, colorless in 2% KOH; paraphyses 100-225 x 15-25 um, cylindric, tips "rounded to subclavate or infrequently subfusoid", septate, colorless to brownish in 2% KOH; elements on sterile ridges 100-175 x 12.5-20 um, septate, "terminal cell clavate or subclavate", colorless or with brownish contents in 2% KOH, (Kuo(6)), spores 23-26(28) x 14.3-16(18) um, (Pilz)