Boraginaceae, the Borage Family
Herbs with alternate entire leaves; sepals 5; petals 5, united, corolla generally regular; stamens 5, attached to the corolla-tube; ovary deeply 4-lobed with a single style.
| 1a. Corolla reddish-purple, about 8 mm. wide (4-10 dm. high; spring) | Hound’s Tongue, Cynoglossum officinale. |
| 1b. Corolla blue with a yellow center, 4-8 mm. wide (1-5 dm. high; spring and early summer) (Forget-me-not) — 13. | |
| 1c. Corolla deep orange, salver-form (2-6 dm. high; spring) (Puccoon) — 15. | |
| 1d. Corolla white or blue, or lightly tinged with yellow or red — 2. | |
| 2a. Corolla rotate, with a very short tube, bright-blue, about 20 mm. broad (3-8 dm. high; summer) | Borage, Borago officinalis. |
| 2b. Corolla tubular, funnel-form, or salver-form — 3. | |
| 3a. Corolla 10 mm. long or more; its tube distinctly longer than the calyx — 4. | |
| 3b. Corolla less than 10 mm. long; its tube equaling or shorter than the calyx — 8. | |
| 4a. Flowers yellowish-white, or somewhat tinged with pink or greenish — 5. | |
| 4b. Flowers blue or purple — 6. | |
| 5a. Corolla-lobes erect; leaves sessile (3-8 dm. high; early summer) | False Gromwell; Onosmodium occidentale. |
| 5b. Corolla-lobes spreading; leaves decurrent (6-10 dm. high; summer) | Comfrey, Symphytum officinale. |
| 6a. Stem and leaves glabrous (3-6 dm. high; spring) | Bluebell, Mertensia virginica. |
| 6b. Stem and leaves pubescent (4-8 dm. high) — 7. | |
| 7a. Corolla regular; leaves ovate or ovate-lanceolate (summer) | Bluebell, Mertensia paniculata. |
| 7b. Corolla irregular; leaves linear-oblong (summer) | Blueweed, Echium vulgare. |
| 8a. Ovary and fruit covered with hooked prickles — 9. | |
| 8b. Ovary and fruit not prickly — 12. | |
| 9a. Principal leaves 2.5 cm. wide or more — 10. | |
| 9b. Principal leaves 2 cm. wide or less (3-8 dm. high; flowers blue or white, summer) (Stickseed) — 11. | |
| 10a. Leaves chiefly basal, the racemes on long leafless peduncles (4-8 dm. high; flowers pale blue, early summer) | Wild Comfrey, Cynoglossum boreale. |
| 10b. Stems leafy (8-12 dm. high; flowers white, summer) | Beggar Lice, Lappula virginiana. |
| 11a. A bract at the base of each flower | Stickseed, Lappula echinata. |
| 11b. Racemes without bracts at the base of each flower | Stickseed, Lappula deflexa var. americana. |
| 12a. Racemes bractless, or bracted only at the base (1-4 dm. high) — 14. | |
| 12b. Raceme with a bract at the base of each flower (flowers white or yellowish) — 17. | |
| 13a. Corolla 4 mm. wide | Forget-me-not, Myosotis laxa. |
| 13b. Corolla 6-8 mm. wide | Forget-me-not, Myosotis scorpioides. |
| 14a. Calyx-lobes all of equal length (summer) | Scorpion Grass, Myosotis arvensis. |
| 14b. Calyx-lobes distinctly unequal in length (spring) | Scorpion Grass, Myosotis virginica. |
| 15a. Corolla-lobes denticulate | Puccoon, Lithospermum angustifolium. |
| 15b. Corolla-lobes entire — 16. | |
| 16a. Flowers sessile; stem softly pubescent | Puccoon, Lithospermum canescens. |
| 16b. Flowers on pedicels 2-5 mm. long; stem hispid or bristly | Puccoon, Lithospermum gmelini. |
| 17a. Corolla white; fruit brown and wrinkled (weed 2-4 dm. high; spring and summer) | Corn Gromwell, Lithospermum arvense. |
| 17b. Corolla yellowish-white; fruit white and smooth (5-10 dm. high) — 18. | |
| 18a. Corolla distinctly surpassing the calyx in length (spring and summer) | Corn Gromwell, Lithospermum officinale. |
| 18b. Corolla equaling or shorter than the calyx (spring) | Wild Gromwell, Lithospermum latifolium. |