Rare Plant Lookalikes

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1. Green trillium (Trillium viride) is state endangered and only occurs in Illinois and Missouri and nowhere else in the world. It looks very similar to prairie trillium (Trillium recurvatum), as both species have sessile flowers. What feature(s) can be used to distinguish between them?

200 answers

a. Flower color

12 votes

6.0%

b. Sepal orientation

74 votes

37.0%

c. Presence of 3 leaves (technically called bracts)

14 votes

7.0%

d. All of the above

100 votes

50.0%

2. Leafy prairie clover (Dalea foliosa) is the only federally endangered plant species in Illinois and only occurs in Wisconsin, Illinois, Alabama and Tennessee. What feature(s) can distinguish it from purple prairie clover (Dalea purpurea)?

184 answers

a. Flower color

14 votes

7.6%

b. Stem hairiness

30 votes

16.3%

c. Number of leaflets per leaf

72 votes

39.1%

d. All of the above

68 votes

37.0%

3. In 1995, Oklahoma grass pink orchid (Calopogon oklahomensis) was newly described from Missouri and its current range includes Illinois. It was formerly lumped with grass pink orchid (Calopogon tuberosus). Both are state endangered in Illinois. What feature(s) can be used to distinguish between them?

160 answers

a. Length of the grass-like leaves

23 votes

14.4%

b. Timing of the blooms

22 votes

13.8%

c. Shape of the upper lip petal

67 votes

41.9%

d. All of the above

48 votes

30.0%

4. Sangamon phlox (Phlox pilosa subsp. sangamonensis) is an endemic subspecies that only occurs in Piatt and Sangamon counties in Illinois. What characteristic separates this state endangered subspecies from the more common and widespread downy phlox (Phlox pilosa subsp. pilosa)?

145 answers

a. Shape of the leaves

50 votes

34.5%

b. Flower color

13 votes

9.0%

c. General hairiness of the stems, leaves and calyx

58 votes

40.0%

d. All of the above

24 votes

16.6%

5. The state endangered kidney-leaf mud plantain (Heteranthera reniformis) is extant in Alexander and Pope counties in Illinois. It’s kidney-shaped leaves are similar to Missouri mud plantain (Heteranthera missouriensis). They both occur in shallow water wetlands and exposed mud. How can one tell them apart?

136 answers

a. Flower color

46 votes

33.8%

b. Number of stamens

22 votes

16.2%

c. Fruit size

14 votes

10.3%

d. All of the above

54 votes

39.7%

6. Wedge-leaved whitlow grass (Draba cuneifolia) is a state endangered species that only occur in Monroe County, but is similar to common whitlow grass (Draba reptans), which is a non-native species. They often occur together on the edge of limestone cliffs. How can one distinguish between them?

127 answers

a. Hairy fruits (siliques)

13 votes

10.2%

b. Stellate hairs on the basal leaves

52 votes

40.9%

c. Flower size

15 votes

11.8%

d. All of the above

47 votes

37.0%

7. There are three species of climbing milkweeds (Matelea spp.) in Illinois and they are virtually indistinguishable vegetatively. What reproductive feature(s) can be used to distinguish between them?

122 answers

a. Exterior surface of the fruits (follicles)

10 votes

8.2%

b. Flower color

30 votes

24.6%

c. Number of seeds per follicle

19 votes

15.6%

d. Only a and b

63 votes

51.6%

8. The rock pinks (Phemeranthus spp.) are small succulent plants that occur on rocky and sandy substrates. There are three species in Illinois. What feature(s) can be used to distinguish between them?

119 answers

a. Size of the flowers

22 votes

18.5%

b. Bloom time (time of day)

21 votes

17.6%

c. Number of stamens

17 votes

14.3%

d. All of the above

59 votes

49.6%

9. An iconic plant of the sandstone canyons of the Shawnee Hills of southern Illinois is the state threatened French’s shooting star (Primula frenchii). It only occurs in Illinois and a few adjacent states and was discovered as new to contemporary science by Dr. George Hazen French at Giant City State Park. How can it be distinguished from the similar looking and more widespread common shooting star (Primula meadia)?

116 answers

a. Flower color

11 votes

9.5%

b. Leaf shape

22 votes

19.0%

c. Habitat

28 votes

24.1%

d. All of the above

55 votes

47.4%

10. American strawberry bush (Euonymus americanus) is a state threatened species that is similar to the native eastern wahoo (Euonymus atropurpureus). Both are desirable species in the wild or the home garden. What is a useful feature in identifying them?

111 answers

a. Surface of the fruit

3 votes

2.7%

b. Flower color

38 votes

34.2%

c. Petiolate vs. sessile leaves

12 votes

10.8%

d. All of the above

58 votes

52.3%

11. Buffalo clover (Trifolium reflexum) is a state threatened species that occurs in scattered locations across Illinois. It has white flowers, but so does the common, non-native, lawn weed white clover (Trifolium repens). How can these plants be identified from each other?

114 answers

a. Serrate leaf margins

21 votes

18.4%

b. Color of the flowers

11 votes

9.6%

c. Leaves occur on the same stems as the flowers

43 votes

37.7%

d. All of the above

39 votes

34.2%

12. The stunningly beautiful superb lily (Lilium superbum) is a rare and formerly state listed species that blooms in the mid-summer in Illinois. It is similar to the more common and widespread Michigan lily (Lilium michiganense). What is the most reliable way to tell them apart?

113 answers

a. Anther length

42 votes

37.2%

b. Stem hairiness

6 votes

5.3%

c. Style color

21 votes

18.6%

d. All of the above

44 votes

38.9%

13. Of the four species of spiderworts in Illinois, only prairie spiderwort (Tradescantia bracteata) is state listed. What feature(s) separates it from the other short statured spiderwort in Illinois, Virginia spiderwort (Tradescantia virginiana)?

111 answers

a. Presence of rhizomes

6 votes

5.4%

b. Glandular hairs on the sepals

61 votes

55.0%

c. Bloom time

8 votes

7.2%

d. All of the above

36 votes

32.4%

14. Illinois wood sorrel (Oxalis illinoensis) was described as new to science in 1982 by retired Illinois State Botanist John Schwegman. It is listed as state endangered. How can it be distinguished from the very common yellow wood sorrel (Oxalis stricta)?

108 answers

a. Flower size

28 votes

25.9%

b. Flower color

14 votes

13.0%

c. Hairiness of the stem

37 votes

34.3%

d. All of the above

29 votes

26.9%

15. There are two species of clubmosses in the Huperzia genus in Illinois. The state threatened cliff clubmoss (Huperzia porophila) is similar to the more widespread shining clubmoss (Huperzia lucidula). How can one distinguish between them?

107 answers

a. Spore color

6 votes

5.6%

b. Leaf shape and margin

46 votes

43.0%

c. Plant size

14 votes

13.1%

d. All of the above

41 votes

38.3%

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