Lab 4 - Asteraceae (Aster Family)

Question 1

identifying characteristics of mature canada thistle

Answer 1

• alternate, oblong to lanceolate leaves
• leaves are lobed, spiny, and slightly clasping with glabrous top and hairy bottom
• tubular flowers that are pink-purple

Question 2

identifying characteristics of mature nodding thistle

Answer 2

• low rosette with very spiny leaves
• distinct silver color around outside of leaves
• stems have 4 sets of winged prickles running up their length
• purple nodding capitulum

Question 3

identifying characteristics of mature scentless chamomile

Answer 3

• finely divided, glabrous leaves that are scentless
• small, white, daisy-type flowers

Question 4

identifying characteristics of mature dandelion

Answer 4

-basal rosette with sharply pointed leaves that point backwards toward center of plant
- bright yellow flower heads

Question 5

identifying characteristics of mature narrow-leaved hawks beard

Answer 5

• narrow leaves with toothing and sessile
• numerous yellow flowers with brown hairs on bracts

Question 6

identifying characteristics of mature prickly lettuce

Answer 6

• clasping leaves with basal lobes
• single row of spines running down underside of mid vein
• yellow flowers

Question 7

identifying characteristics of mature common groundsel

Answer 7

-prominent keeled midvein on leaves
- yellow tubular florets with black tips on bracts

Question 8

identifying characteristics of mature canada fleabane

Answer 8

• petiolate rosette leaves that are pubescent and coarse toothing
• stem leaves packed closely on the stem
• pubescent stem

Question 9

identifying characteristics of mature pineapple weed

Answer 9

• finely divided, smooth leaves that are slightly fleshy
• has odor when crushed
• tiny yellow tubular florets

Question 10

identifying characteristics of mature absinth

Answer 10

• leaves with rounded lobes and silvery hair
• leaves are deeply divided and have greenish grey color

Question 11

identifying characteristics of mature perennial sow thistle

Answer 11

• smooth stem at base, slightly hairy towards top
• alternate leaves that are deeply lobed but do not go all the way to the central vein
• spines along leaf margin

Question 12

identifying characteristics of mature annual sow thistle

Answer 12

• deeply lobed leaves all the way to central vein and basal/terminal lobes
• dull, light green leaves with soft prickles

Question 13

identifying characteristics of mature spiny annual sow thistle

Answer 13

• shallowly lobed leaves with very spiny margin
• leaves clasp the stem
• upper surface of leaves dark and glossy, lower surface pale green