What’s a dichotomous key?
Help
Salix key for staminate reproductive material
See list of 30 species in this subkey-
1a. Flowers with an abaxial nectary (or nectaries) in addition to the adaxial nectary (or nectaries)
-
2a. Flowers each with 3–10 stamens
-
3a. Rachis of anther sac curved; floral bracts entire at apex (sometimes toothed in S. amygdaloides; aments loosely flowered; flowers ± in whorls about the rachis of the ament
-
4a. Branchlets brittle at base, breaking ± cleanly at the junction of yearly growth; expanding leaf blades green on both surfaces
-
4b. Branchlets flexible at base, tearing when bent to failure; expanding leaf blades glaucous on the abaxial surface
-
-
3b. Rachis of anther sac straight; floral bracts entire, toothed, or erose at apex; aments densely flowered; flowers spirally arranged about the rachis of the ament
-
5a. Emerging leaves with stipules and often with red-brown hairs
-
5b. Emerging leaves exstipulate (sometimes with minute stipule rudiments) and without red-brown hairs
-
6a. Floral bracts sparsely pubescent, the hairs mainly near the apex; aments 27–81 mm long; emerging leaves with abaxially green blades; non-native trees 5–15 mm tall
-
6b. Floral bracts moderately to densely pubescent throughout abaxial surface; aments 11–31 (–53) mm long; emerging leaves with abaxially glaucous blades (this sometimes difficult to detect on early emerging blades); native shrubs 1–5 m tall
-
-
-
-
2b. Flowers each with 1 or 2 stamens [Fig. 892]
-
7a. Flowers each with 1 stamen, or appearing as 1 due to fusion of the filaments
-
8a. At least some of the aments opposite or subopposite; flowers with 2 stamens but with filaments connate their entire length, bearing 2 anthers at the apex; upright shrubs 1.5–5 m tall
-
8b. Aments all alternate; flowers with 1 stamen (i.e., only 1 anther at the summit of the filament); dwarf shrubs rarely exceeding 0.15 m
-
-
7b. Flowers each with 2 stamens [Fig. 892]
-
9a. Aments 3–7.5 ×1.5–5 mm, with 5–12 flowers; flowering branchlets 0.2–2 mm long
-
9b. Aments 10–61 ×4–16 mm, with more than 12 flowers; flowering branchlets (1–) 2–20 mm long
-
10b. Floral bracts yellow-brown to green-yellow or white-brown, sometimes suffused with red near the apex [Fig. 887]; filaments pilose, at least in the basal portion; aments 20–61 mm long
-
11a. Petioles of emerging leaves eglandular; filaments densely pilose in the basal half
-
11b. Petioles of emerging leaves glandular at the summit; filaments sparsely pilose only at the base
-
-
-
-
-
1b. Flowers with only an adaxial nectary
-
12a. Filaments pubescent (though sometimes sparsely), at least near the base
-
13a. Floral bracts yellow-brown or pale green-yellow, often suffused with red at the apex [Fig. 887]
-
14a. Filaments basally connate for up to slightly more than ½ their length
-
15a. Aments borne on flowering branchlets 1–1.5 mm long; expanding leaves mostly linear to narrow-oblong or narrow-oblanceolate
-
15b. Aments borne on flowering branchlets 0.5–11 mm long; expanding leaves mostly elliptic or oblong to oblanceolate or obovate (in part)
-
-
14b. Filaments distinct
-
16a. Decorticated wood smooth, with small points or with a few short ridges generally shorter than 5 mm (in part)
-
16b. Decorticated wood (i.e., with the bark removed) of 1- to 4-year-old branches with many prominent ridges, some longer than 20 mm (in part)
-
-
-
-
17a. Decorticated wood (i.e., with the bark removed) of 1- to 4-year-old branches with many prominent ridges, some longer than 20 mm [Fig. 890]
-
18a. Aments 15.5–21.5 ×10–15 mm; floral bracts 1–2.2 mm long; anthers 0.5–0.8 mm long (in part)
-
18b. Aments 26–39 ×12–26 mm; floral bracts 2–3 mm long; anthers 0.7–1 mm long
-
-
17b. Decorticated wood smooth, with small points, or with a few short ridges generally shorter than 5 mm
-
19a. Aments coetaneous (i.e., expanding with the leaves) [Fig. 888]
-
20a. Branchlets brittle at base, breaking ± cleanly at the junction of yearly growth; expanding leaves without red-brown hairs; aments 13.5–40 mm long
-
20b. Branchlets flexible at base, tearing when bent to failure; expanding leaves often with red-brown hairs; aments 12–29 mm long
-
-
19b. Aments precocious (i.e., expanding before the leaves) [Fig. 894]
-
21a. Floral bracts 2–4 mm long; anthers yellow; small trees 8–15 m tall
-
21b. Floral bracts 0.8–2.5 mm long; anthers yellow or purple initially, later turning yellow; dwarf shrubs to tall shrubs 0.3–4 (–8) m tall
-
22a. Anthers 0.5–1 mm long; aments 23–52 mm long; adaxial nectaries 0.6–1.1 mm long
-
22b. Anthers 0.4–0.6 mm long; aments (5–) 6–20 (–34) mm long; adaxial nectaries 0.2–0.7 mm long
-
23a. Staminate aments (10–) 14–20 (–34) mm long, with floral bracts 1.4–1.6 mm long; generally upright shrubs 0.3–3 m tall (in part)
-
23b. Staminate aments (5–) 6–11 (–13) mm long, with floral bracts 0.8–1.6 mm long; decumbent shrubs 0.3–0.7 m tall (in part)
-
-
-
-
-
-
-
12b. Filaments glabrous throughout
-
24a. Aments precocious (i.e., expanding before the leaves) [Fig. 892]
-
25a. Plants of subalpine and alpine communities, elevation usually exceeding 900 m
-
25b. Plants not of alpine areas, elevation less than 900 m
-
26a. Branchlets prominently glaucous
-
26b. Branchlets not glaucous
-
27a. Anthers 0.6–0.8 mm long; adaxial nectaries 0.6–1.5 mm long; second year branches usually yellow to yellow-brown or gray-brown (in part)
-
27b. Anthers 0.4–0.6 mm long; adaxial nectaries 0.2–0.7 mm long; second year branches usually red-brown to dark red-brown
-
28a. Staminate aments (10–) 14–20 (–34) mm long, with floral bracts 1.4–1.6 mm long; generally upright shrubs 0.3–3 m tall (in part)
-
28b. Staminate aments (5–) 6–11 (–13) mm long, with floral bracts 0.8–1.6 mm long; decumbent shrubs 0.3–0.7 m tall (in part)
-
-
-
-
-
24b. Aments coaetaneous or serotinous (i.e., expanding with or after the leaves, respectively) [Fig. 888]
-
29a. Floral bracts yellow-brown or pale green-yellow, often suffused with red at the apex [Fig. 887]
-
30a. Second-year branches usually pubescent, dull to sublustrous; aments subglobose to short-obloid, 10–42 mm long (in part)
-
30b. Second-year branches glabrous and lustrous; aments short-obloid to cylindric, 18.5–63 mm long
-
-
-
31a. Dwarf, colonial plants 0.03–0.15 m tall, of alpine communities, elevation exceeding 1000 m
-
31b. Short shrubs to small trees 0.3–7 m tall, not of alpine communities, of lower elevations
-
32a. Branchlets and often the second-year branches conspicuously pubescent with white tomentum (i.e., the hairs crimped and tangled; glabrescent in rare forms)
-
32b. Branchlets and branches glabrous or pubescent with pilose, villous, or veluntinous hairs (i.e., the hairs not crimped and tangled)
-
33a. Expanding leaf blades from vegetative buds with serrulate margins (rarely entire in S. eriocephala); first leaves with foliaceous stipules (sometimes minute in S. myricoides)
-
34a. Floral bracts 0.8–1.5 (–1.6) mm long, pubescent with wavy hairs; anthers 0.4–0.64 mm long
-
34b. Floral bracts (1.2–) 1.5–3 mm long, pubescent with straight hairs; anthers 0.52–0.76 mm long
-
-
33b. Expanding leaf blades with entire margins; first leaves exstipulate or with minute stipules
-
35a. Floral bracts 0.8–1.6 mm long, pubescent abaxially mainly near the apex; aments 11–21 mm long; anthers 0.4–0.6 mm long
-
35b. Floral bracts 1.6–2.2 mm long, pubescent abaxially throughout the surface; aments 24–48 mm long; anthers 0.6–0.8 mm long (in part)
-
-
-
-
-
-
-
Show photos of:
Each photo represents one species in this subkey.