What’s a dichotomous key?
Help
Spiraea
See list of 6 species in this genusThe name Spiraea salicifolia L. was at one time used for our species of western New England now called S. alba var. alba (e.g., Wiegand 1900). Recent reports of S. salicifolia in New England (e.g., Magee and Ahles 1999) are erroneous, as they were based on older publications that were referring to S. alba var. alba.
-
1a. Inflorescence a simple umbel or corymb, terminating a short-shoot [Fig. 873]
-
2a. Inflorescences (except sometimes the uppermost) borne on a peduncle, with 5–12 flowers; petioles 4–7 mm long; follicles pubescent with appressed hairs
-
2b. Inflorescences sessile, with 3–7 flowers [Fig. 873]; petioles 1–4 mm long; follicles glabrous or sometimes pubescent along the adaxial suture in S. prunifolia
-
3a. Leaf blades ovate to oblong-lanceolate, pubescent on the abaxial surface; pedicels 10–24 mm long, pubescent
-
3b. Leaf blades narrow-lanceolate, glabrous on the abaxial surface; pedicels 6–10 mm long, glabrous
-
-
-
1b. Inflorescence a panicle or compound corymb (i.e., with branches), terminating a long-shoot [Fig. 872]
-
4a. Inflorescence a compound corymb, as wide as or wider than tall; leaf blades (5–) 8–15 cm long
-
4b. Inflorescence a panicle, mostly wider than tall (except in high-elevation plants) [Fig. 872]; leaf blades 3–7 (–8) cm long
-
5a. Mature leaf blades with white or red-brown tomentum abaxially; branchlets tomentose, especially about the nodes; flowers without a nectar disk; sepals reflexed in fruit; follicles pubescent
-
5b. Mature leaf blades ± glabrous abaxially; branchlets ± glabrous; flowers with a nectar disk; sepals erect in fruit; follicles glabrous
-
-
Show photos of:
Each photo represents one species in this genus.