Ageratina shastensis

(D. W. Taylor & Stebbins) R. M. King & H. Robinson

Phytologia 45: 464. 1980.

Common names: Mt. Shasta snakeroot
Endemic
Basionyms: Eupatorium shastense D. W. Taylor & Stebbins Madroño 25: 218, fig. 1. 1978
Treatment appears in FNA Volume 21. Treatment on page 552. Mentioned on page 548, 553.

Perennials, 15–45 cm (bases woody, enlarged, occasionally rhizomatous). Stems erect (clustered from bases), puberulent to pubescent (often with some glandular-hairs distally). Leaves opposite proximally, alternate on at least distal 1/2 of stems; petioles 4–6 mm; blades (venation raised-reticulate) orbiculate (juvenile) or deltate-ovate, 1.5–3 × 1–2 cm, (subcoriaceous) bases obtuse to truncate, margins entire or coarsely serrate to dentate, apices acute to acuminate, abaxial faces ± glanddotted and/or stipitate-glandular. Heads mostly borne singly (each often subtended by a leaflike bract). Peduncles (0–) 2–15 mm, puberulent and stipitate-glandular. Involucres 10–11 mm. Phyllaries: apices acute, abaxial faces sparsely puberulent. Corollas white, glabrous. Cypselae hispidulous. 2n = 34.


Phenology: Flowering Jun–Oct.
Habitat: Cracks and crevices of nearly vertical limestone cliffs
Elevation: 400–1800 m

Discussion

Ageratina shastensis is recognized by relatively large solitary heads and coarsely serrate, subcoriaceous leaves alternate on distal parts of stems.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

... more about "Ageratina shastensis"
puberulent +  and stipitate-glandular +
not tailed +, truncate +, rounded +  and obtuse +
scarious +
usually ovate +  and lanceolate +
usually terete +  and clavate +
indeterminate +  and determinate +
Guy L. Nesom +
(D. W. Taylor & Stebbins) R. M. King & H. Robinson +
obtuse to truncate +
enlarged +
Eupatorium shastense +
3(-5)-nerved +
1.5 cm15 mm <br />0.015 m <br /> (3 cm30 mm <br />0.03 m <br />) +
dissected +, lobed +, toothed +  and entire +
deltate-ovate;orbiculate +
1cm;2cm +
papillate +  and rugose +
(4-)5-angled;10-ribbed +
Mt. Shasta snakeroot +
scabrellous +
fusiform +  and prismatic +
fertile +  and bisexual +
400–1800 m +
puberulent +, pilose +, hispidulous +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Cracks and crevices of nearly vertical limestone cliffs +
indeterminate +
each +  and sessile +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
campanulate +
1 cm10 mm <br />0.01 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
alternate +  and opposite +
lanceolate +  and lance-linear +
dentate +, serrate +  and entire +
2-carpellate +
persistent +
0 cm0 mm <br />0 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
stipitate-glandular +  and puberulent +
0.2 cm2 mm <br />0.002 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Flowering Jun–Oct. +
2-nerved +  and 0-nerved +
8 +  and 30 +
subequal +  and unequal +
bearing subulate enations +, hairy +  and bristly +
exalbuminous +
appendaged +  and truncate +
hirsutulous +
papillate +
Compositae +
Ageratina shastensis +
Ageratina +
species +
obconic +  and campanulate +
15 cm150 mm <br />0.15 m <br /> (45 cm450 mm <br />0.45 m <br />) +
shrub +  and subshrub +