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- Nabalus boottii
Nabalus boottii — Boott's rattlesnake-root
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Facts
Boott's rattlesnake-root is a globally-rare species, endemic to the Northeastern United States and represented by a handful of populations in New York and New England, where it occurs only in alpine habitats of Maine, New Hampshire and Vermont. It is named after John Wright Boott (1788-1845) who first collected the plant in 1829 in the White Mountains of New Hampshire.
Habitat
Alpine or subalpine zones, ridges or ledges
New England distribution
Adapted from BONAP data
Native: indigenous.
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
Found this plant? Take a photo and post a sighting.
Characteristics
- Habitat
- terrestrial
- New England state
- 
                                
                                    - Maine
- New Hampshire
- Vermont
 
- Leaf type
- leaves are simple (lobed or unlobed but not separated into leaflets)
- Leaf arrangement
- 
                                
                                    - alternate: there is one leaf per node along the stem
- the leaves are growing only at the base of the plant (basal)
 
- Leaf blade edges
- 
                                
                                    - the edge of the leaf blade has no teeth or lobes
- the edge of the leaf blade has teeth
 
- Flower type in flower heads
- the flower head has ray flowers only, meaning all of the individual flowers of the flower head have a strap-shaped ray, which may or may not have teeth at the very tip of the ray
- Ray flower color
- white
- Tuft or plume on fruit
- at least a part of the plume is made up of fine bristles
- Spines on plant
- the plant has no spines
- Leaf blade length
- 20–80 mm
- Disk flower number
- NA
- 
                        Flowers- Bract color
- the bracts are not colored or tinged with with pink, red or purple
 - Bract cycle number
- there is one main cycle of bracts
 - Bract outer side hair type
- the bracts are not hairy on their outer surface
 - Bract outer side hairs
- the bracts are not hairy on their outer surfaces
 - Bract shape
- 
                                
                                    - the main bracts are lanceolate (widest above the base, then taper narrowly towards the tip)
- the main bracts are of a different shape than the given options
 
 - Bract spines
- the bracts have no spines
 - Bract tip shape
- the tips of the bracts acute (have a sharp point)
 - Bracts
- the bracts in separate cycles are similar or gradually changing from the outer to inner cycles
 - Disk flower color
- NA
 - Disk flower lobe number
- NA
 - Disk flower number
- NA
 - Disk flower proportions
- NA
 - Disk flower reproductive parts
- NA
 - Disk flower shape
- NA
 - Flower head number
- each flowering stem has four or more flower heads on it
 - Flower head outer flowers
- at the outer edge of the flower head, each flower has a single enlarged lobe or strap
 - Flower head platform
- the base has no bristles or papery scales
 - Flower head profile
- the disk is rounded across the top
 - Flower head shape
- 
                                
                                    - NA
- the sides of the flower head are roughly parallel, like a cylinder
 
 - Flower type in flower heads
- the flower head has ray flowers only, meaning all of the individual flowers of the flower head have a strap-shaped ray, which may or may not have teeth at the very tip of the ray
 - Height of flower head base
- 8–12 mm
 - Inflorescence shape
- the inflorescence is not flat-topped but appears rounded, with some flower heads distinctly higher than others
 - Number of bracts at flower head base
- 3–15
 - Ovary beak
- 
                                
                                    - there is a beak on the ovary
- there is no beak on the ovary
 
 - Ovary cross-section
- the ovary has five or more corners in cross-section
 - Ovary hair type
- the ovary has no hairs on it
 - Ovary hairs
- the ovary has no hairs on it
 - Ovary lines or ribs
- 
                                
                                    - there are seven to nine ribs visible on the ovary
- there are ten or more ribs visible on the ovary
 
 - Ovary surface
- the ovary surface has no points, bumps or wrinkles, though it may have lines, ribs or wings
 - Ray flower color
- white
 - Ray flower reproductive parts
- the ray flowers have both carpels and stamens
 - Ray flowers
- 
                                
                                    - 11-15
- 16-25
- 6-10
 
 - Ray length
- 7–13 mm
 - Reproductive system
- NA
 - Smaller bracts at base of bracts
- there is no smaller, outer cycle of bracts
 - Swelling at base of flower head
- the peduncles are not swollen, or only slightly
 - Width of flower head base
- 5–6 mm
 
- 
                        Fruits or seeds- Number of pappus parts
- 11 or more
 - Ovary length in developed fruit
- 5–6 mm
 - Seed hair tuft color
- 
                                
                                    - the pappus hairs are another color
- the pappus hairs are tan to dark brown
 
 - Seed hair tuft details
- the pappus hairs are hooked or barbed
 - Seed hair tuft length
- 6–8 mm
 - Seed hair tuft tips
- the pappus hairs are slender
 - Seed tuft type
- the pappus is made of very fine hairs or bristles
 - Tuft or plume on fruit
- at least a part of the plume is made up of fine bristles
 
- 
                        Glands or sap- Sap
- the sap is milky and opaque, and may be white or colored
 
- 
                        Growth form- Growth form
- the plant has one or more free-standing stems
 - Plant lifespan
- the plant is perennial, it shows evidence of previous year's leaves, stems or stem bases
 - Spines on plant
- the plant has no spines
 - Underground organs
- 
                                
                                    - the plant has one or more swollen storage organs underground, such as bulbs, tubers or corms
- there is a thickened taproot on the plant
 
 
- 
                        Leaves- Final leaf segment length (compound lvs only)
- 0 mm
 - Final leaf segment width (compound lvs only)
- 0 mm
 - Hairs on underside of leaf blade
- the underside of the leaf is not hairy, or has very few hairs
 - Hairs on upper side of leaf blade
- the upper side of the leaf is not hairy, or has very few hairs
 - Leaf arrangement
- 
                                
                                    - alternate: there is one leaf per node along the stem
- the leaves are growing only at the base of the plant (basal)
 
 - Leaf blade base
- the leaf has a distinct petiole
 - Leaf blade base shape
- the base of the leaf is cordate (heart-shaped) or sagittate (arrow-shaped)
 - Leaf blade edges
- 
                                
                                    - the edge of the leaf blade has no teeth or lobes
- the edge of the leaf blade has teeth
 
 - Leaf blade hairs
- NA
 - Leaf blade length
- 20–80 mm
 - Leaf blade shape
- 
                                
                                    - the leaf blade is elliptic (widest near the middle and tapering at both ends)
- the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
- the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
- the leaf blade is triangular, with the stalk or attachment point on one of the sides
 
 - Leaf blade tip
- 
                                
                                    - the tip of the leaf blade is acute (sharply pointed)
- the tip of the leaf blade is obtuse (bluntly pointed)
 
 - Leaf blade width
- 5–30 mm
 - Leaf disposition
- the lower leaves are larger, toothier, and/or on longer stalks than the upper leaves
 - Leaf spines
- there are no spines on the leaf edges
 - Leaf type
- leaves are simple (lobed or unlobed but not separated into leaflets)
 - Leaflet number
- 0
 - Specific leaf type
- the leaves are simple (lobed or unlobed but not separated into leaflets
 
- 
                        Place- Habitat
- terrestrial
 - New England state
- 
                                
                                    - Maine
- New Hampshire
- Vermont
 
 - Specific habitat
- 
                                
                                    - alpine or subalpine zones
- ridges or ledges
 
 
- 
                        Stem, shoot, branch- Leaves on stem
- there is at least one full leaf above the base of the flowering stem
 - Stem internode hair direction
- the hairs point mostly upwards to outwards
 - Stem internode hair type
- 
                                
                                    - the hairs on the stem are plain, without glands or branches, and not tangled
- the stem has no hairs between the nodes
 
 - Stem internode hairs
- the stem has hairs between the nodes
 
Wetland status
Not classified
In New England
Distribution
- Connecticut
- absent
- Maine
- present
- Massachusetts
- absent
- New Hampshire
- present
- Rhode Island
- absent
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Maine
- extremely rare (S-rank: S1), endangered (code: E)
- New Hampshire
- extremely rare (S-rank: S1), endangered (code: E)
- Vermont
- extremely rare (S-rank: S1), endangered (code: E)
From Flora Novae Angliae dichotomous key
3. Nabalus boottii DC. NC
Boott’s rattlesnake-root. Prenanthes boottii (DC.) Gray • ME, NH, VT. Alpine plateaus and ridges.
Native to North America?
Yes
 
                        ![Leaves: Nabalus boottii. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-239x239/Asteraceae/nabalus-boottii-le-ahaines-c.jpg) 
                         
                         
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