North American species of Lactarius / L. R. Hesler, Alexander H. Smith.

Appendix II

575

The absence of data on the latex makes it impossible to place the
species in our classification. We have studied the type from Kew. It
consists of six basidiocarps affixed to a card and sections were not
feasible. Gill fragments were mounted in Melzer's and the spores
found to be smooth and nonamyloid; no Lactarius spores were found.
Lactarius insulsus (Fr.) Fr. var. insulsus Epicr. Myc., p. 336. 1838
Agaricus insulsus Fr., Sys. Myc. 1: 68. 1821.
Pileus 4-12(22) cm broad, convex, depressed to subumbilicate, finally infundibuliform, "cream buff," "light buff," "warm buff,"
"pale pinkish buff," to "ochraceous orange," viscid, zonate, or more
rarely subzonate, glabrous, margin even or in age with short striae.
Context white; odor slight or mild, taste acrid. Latex white, unchanging, not staining, taste acrid.
Lamellae adnate-subdecurrent, white, becoming yellowish or
ochraceous buff, close, rather narrow, some forking behind, lamellulae
numerous.
Stipe 3-5(8) cm long, 6-25(35) mm thick, white becoming more
or less concolorous with the pileus, viscid, scrobiculate to faintly so or
not at all, hollow.
Spores in deposit "cream color" to "Naples yellow," 6-8.5(9) X
5.5-7(7.5) #, warts 0.3-0.6 ju, 4-spored. Pleurocystidia 40-68(90) X 4-8
/s, slender-ventricose, acuminate; cheilocystidia 36-45 X 4-6 Au, similar.
Pileus cuticle an ixocutis; hypodermium present. Stipe cuticle an ixocutis; rosettes present. Clamp connections none.
Habit, Habitat, and Distribution.-On soil, in mixed woods, North
Carolina, Tennessee, and Ohio, July-September; also Europe.
Material cited.-NORTH CAROLINA: Hesler 9349, 26483, 26492,
26510, 35206; OHIO: Cooke 35933 (MICH); TENNESSEE: Hesler
4123, 4278, 5423, 5428, 7950, 11753, 11758, 12898, 20550, 23054,
21847, 28203, 29343, 30275, 30278, 35216, 35218, 35221, 35229, 35375;
THE NETHERLANDS: Bas 1990 (TENN 35818), 2462; Kits van
Waveren, August 16, 1960.
Observations.-This species is characterized by its buff, zonate,
viscid pileus; its white, unchanging, acrid latex; its whitish to pale
buff, viscid stipe; and its yellowish spores. In general appearance, it
resembles L. zonarius with which it seems to have been confused;
but, in L. insulsus the stipe is viscid (there is a well-developed ixocutis), and in L. zonarius the stipe cuticle is dry (the cuticle is composed of dry, repent hyphae). The European L. zonarioides Kiihner
and Romagn. differs from L. insulsus in its larger spores, and in the
fact that the lamellae, when bruised, stain olive-green.