Silybum marianum — blessed milk-thistle

Characteristics

• Flowers

  Bases of bract appendages

  NA

  Bract cycle number

  there are three or more cycles of bracts

  Bract margins

  • NA
  • there are fine hairs along the bract margins

  Bract outer side hair type

  the bracts are hairy, with simple hairs on their outer surface

  Bract outer side hairs

  the bracts are hairy on their outer surfaces

  Bract spines

  there is just one simple spine at the tip of the bract

  Bract tip extension appearance

  the projections from the bract tips have further projections from their edges, like a fringe

  Bract tip extension edge

  there are projections from the bract tips

  Bract tip orientation

  the bracts are pressed against the plant, or spreading out at the tips

  Bracts

  there are at least two distinct forms of bracts in different cycles

  Disk flower color

  • blue to purple
  • pink to red

  Disk flower lobe number

  5

  Disk flower number

  • 21-50
  • more than 50

  Disk flower reproductive parts

  the disk flower has both pollen- and seed-producing parts

  Disk flower shape

  the disk flower is tube-shaped (cylindrical), or gradually widening like a funnel

  Disk width

  30–60 mm

  Flower head number

  each flowering stem has only one to three flower heads on it

  Flower head outer flowers

  at the outer edge of the flower head, the flowers have no enlarged lobe or strap, and are of similar size as those in the center of the disk

  Flower head platform

  the base has no bristles or papery scales

  Flower head platform surface

  NA

  Flower head position

  each of the flower heads is separate on its own peduncle (stalk), not clustered in groups

  Flower head profile

  the disk is flat or nearly flat across the top

  Flower head shape

  NA

  Flower head width

  30–60 mm

  Flower type in flower heads

  the flower head has disk flowers only, and lacks the strap-shaped flowers

  Height of flower head base

  15–60 mm

  Inflorescence branching (Solidago)

  NA

  Inflorescence shape

  the flower heads grow in clusters from the axils of the branches or leaves

  Inflorescence stem

  • hairs are present on the stem of the inflorescence
  • the stem of the inflorescence is not hairy

  Ovary cross-section

  the ovary is compressed (flattened)

  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 no lines or ribs visible on the ovary

  Ovary profile

  in profile, the ovary is roughly egg-shaped

  Ray flower color

  NA

  Ray flower reproductive parts

  NA

  Ray flowers

  0

  Ray length

  0 mm

  Reproductive system

  all the flowers on the plant contain both carpels and stamens

  Scale tip

  NA

  Smaller bracts at base of bracts

  there is a cycle of much smaller bracts outside the cycle of larger and longer bracts

  Style branch number

  the style has two branches

  Width of flower head base

  15–60 mm

• Fruits or seeds

  Ovary length in developed fruit

  6–8 mm

  Ovary width in developed fruit

  2.5–4 mm

  Seed hair tuft bases

  the pappus hairs are attached to one another near the base

  Seed hair tuft details

  • the pappus hairs are hooked or barbed
  • the pappus hairs are smooth and plain

  Seed hair tuft length

  15–20 mm

  Seed hair tuft tips

  • at least some of the pappus hairs are broader at their tips than their bases
  • the pappus hairs are slender

  Seed hairs uniform

  there are two distinct lengths of pappus hairs

  Seed tuft type

  • the pappus is made of flat scales that look split or frayed at the tips
  • the pappus is made of very fine hairs or bristles

  Top of disk flower ovary

  NA

  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 clear and watery

• Growth form

  Growth form

  the plant has one or more free-standing stems

  Plant lifespan

  • the plant is annual, it lacks evidence of previous years' growth
  • the plant is biennial, it appears as either first year (non-reproductive) plants or second year plants with flowers or fruit

  Spines on plant

  there are spines on the plant

  Underground organs

  there is a thickened taproot on the plant

• Leaves

  Hairs on underside of leaf blade

  • the underside of the leaf is fuzzy or hairy
  • 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 fuzzy or hairy
  • 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
  • the leaf has no petiole
  • the leaf has no petiole and at the base it clasps the stem, or goes all the way around the stem so the stem appears to pierce the leaf

  Leaf blade base shape

  • NA
  • the base of the leaf blade is cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow

  Leaf blade bloom

  the underside of the leaf has no noticeable bloom

  Leaf blade edges

  • the edge of the leaf blade has lobes, or it has both teeth and lobes
  • the edge of the leaf blade has teeth

  Leaf blade hairs

  • NA
  • the leaf blade has simple hairs with no glands, and not tangled or wooly

  Leaf blade length

  150–600 mm

  Leaf blade surface colors

  there are noticeable spots, patches or stripes on the upper surface of the leaf

  Leaf blade veins

  the leaf blade has one main vein running from the base towards the tip

  Leaf blade width

  Up to 200 mm

  Leaf disposition

  • the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
  • the lower leaves are larger, toothier, and/or on longer stalks than the upper leaves

  Leaf spines

  there are spines along the leaf edges

  Leaf stalk

  • the leaves have leaf stalks
  • the leaves have no leaf stalks, but attach directly to the stem

  Leaf type

  leaves are simple (lobed or unlobed but not separated into leaflets)

  Leaflet number

  0

  Specific leaf type

  the leaf has a row of two or more lobes on each side of the central axis

• Place

  Habitat

  terrestrial

  New England state

  • Connecticut
  • Massachusetts
  • New Hampshire

  Specific habitat

  man-made or disturbed habitats

• Stem, shoot, branch

  Stem internode hair direction

  the hairs point mostly upwards to outwards

  Stem internode hair type

  • at least some of the hairs on the stem are tangled, matted or woolly
  • the stem has no hairs between the nodes

  Stem internode hairs

  • the stem has hairs between the nodes
  • the stem has no hairs between the nodes

Wetland status

Not classified

In New England

From Flora Novae Angliae dichotomous key