from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Having or resembling a knob or knoblike protuberance.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Having an umbo
from the GNU version of the Collaborative International Dictionary of English
- adj. Having a conical or rounded projection or protuberance, like a boss.
from The Century Dictionary and Cyclopedia
- Having a boss or umbo, as a shield or disk of any sort.
- In zoology: Formed into an umbo, a boss, or a knob; button-like; umbonal; umbonic.
- Having an umbo, as a shell; bearing umbones of this or that kind; umbonated: as, both valves strongly umbonate.
- In botany, bearing an umbo or boss in the center, as the pileus of many species of Agaricus.
Pileus, scaly or warted.campanulate. silky, cracked or fibrillose.umbonate. umbilicate. striate.
+Cap+ a golden brown or bright cinnamon color, 1½ to 4 inches broad, umbonate, silky, shining, squamulose, with yellowish fibrils, and then smooth.
+Cap+ a pale red color, 2 to 3 inches broad, convex when young, then slightly raised in the middle, umbonate, afterward the margin is elevated and the cap becomes funnel-shaped and the margin wavy.
+Cap+ whitish-violet, 2 to 3 inches broad, fleshy, convex, broadly umbonate or gibbous, dry, beautifully silky and becoming even; flesh juicy, a bluish-white color.
+Cap+ brownish and turning to yellow, 1 to 3 inches broad and slightly umbonate, flesh whitish.
The disc in some specimens was slightly raised in the middle, almost umbonate.
_Omphalia_ the pileus is umbilicate in such species, while in _Mycena_ it is blunt or umbonate.
The = pileus = is convex, then expanded, the margin more or less inrolled, then incurved, prominently umbonate, very viscid when moist, the ground color a saffron yellow or in the center burnt umber to wood brown.
The = pileus = is conic in some plants, to convex and umbonate, thin, minutely scaly with blackish hairy scales, dull heliotrope purple, darker on the umbo.
The entire plant is bay brown, becoming ochraceous in color, and the margin of the cap in age is striate, first bell-shaped, then convex and somewhat umbonate.