Lab 6 - Poisonous Weeds

Question 1

identifying characteristics of mature spotted water hemlock

Answer 1

• erect purple brown streaked stem with swollen base
• doubly compound pinnate, alternate leaves with toothed leaflets
• leaflet veins end in notches along margin
• ## small white flowers in a compound umbel

Question 2

identifying characteristics of mature water parsnip

Answer 2

• compound pinnate leaves with linear leaflets and fine serrations
• veins of leaflets end at tip of serration
• yellow flowers

Question 3

identifying characteristics of mature death camas

Answer 3

• short stem with basal leaves
• thick linear leaves with parallel veins that are v-shaped in cross-section
• creamy white flowers in a raceme

Question 4

identifying characteristics of mature seaside arrowgrass

Answer 4

• very short stem with basal leaves
• long narrow leaves with parallel vein that have semi-circle cross section
• small, pale-green flowers in racemes that are well above leaf height

Question 5

identifying characteristics of mature field horsetail

Answer 5

• hollow stem
• conspicuous joints with whorled toothed bracts

Question 6

identifying characteristics of mature stinging nettle

Answer 6

• hair on leaf and stem
• opposite, cordate to deltoid leaves with toothing
• greyish green, dioecious, and axillary flowers

Question 7

identifying characteristics of mature round leaf mallow

Answer 7

• alternate, round, shallowly lobed leaves with a long petiole
• inconspicuous white to pink flowers found in axillary clusters

Question 8

identifying characteristics of seedling round leaf mallow

Answer 8

-heart-shaped cotyledons with rounded lobes and 3 pale-white lines

Question 9

identifying characteristics of mature portulaca

Answer 9

• alternate, succulent, tear-shaped leaves
• leaves are sessile and tinged red
• small yellow, inconspicuous flowers in axillary clusters

Question 10

identifying characteristics of seedling portulaca

Answer 10

• highly succulent cotyledons
• cotyledons have short petioles and linear

Question 11

identifying characteristics of mature rough cinquefoil

Answer 11

• stem covered in stiff red hairs
• trifoliate leaves with 3 oblong leaflets with stipules
• looks like strawberry
• yellow flowers with 5 petals in cyme inflorescence

Question 12

identifying characteristics of mature northern willowherb

Answer 12

• basal rosette with lanceolate to elliptical leaves
• once bolting, leaves become opposite
• pubescent stem near base
• small purple flowers with small cleft in petal (terminal raceme)

Question 13

identifying characteristics of mature black medick

Answer 13

• alternate, compound trifoliate leaves with sharply pointed stipules
• prostrate growth
• pealike, small, yellow flowers

Question 14

identifying characteristics of black medick seedling

Answer 14

• oval, sessile cotyledons
• first true leaf is oval with long petiole
• looks like alien