Key to Specimens with Male Flowers
1a. Stamens 2 (counting in several flowers if at all possible).
2a. Leaves 12-17 (-25) cm broad, the base attenuate; young branchlets 4- or 6-angular or sulcate, densely covered with minute peltate scales or stellate lepidote-hairs (Fig. 22 B).
2b. Leaves (3-) 5-8 (-11) cm broad, oblong, lanceolate, elliptic, or obovate, the base acute to obtuse; young branchlets terete, with stellate or simple hairs.
3a. Branchlets and upper leaf surface minutely stellate-pubescent, leaf surface in older leaves usually glabrescent.
3b. Branchlets and upper leaf surface with simple, 1-4 mm long, yellow hairs, the hairs persistent.
1b. Stamens more than 2.
4a. Leaves ascending, petioles 0.2-0.5 cm long, leaves 5-6 (-8) cm long and 2.5-3 (-4) cm broad.
4b. Leaves spreading or drooping, petioles longer than 0.5 cm, leaves larger than the above.
5a. Leaf margin entire; plants usually monoecious.
6a. Cymes in subsessile clusters, 1-1.5 cm long.
7a. Tepals minute, about 0.5 mm long.
7b. Tepals 2-3.5 mm long.
6b. Cymes at least 2 cm long, commonly 3-4 cm or longer.
8a. Flowers with 10-23 (-30) stamens.
9a. Flowers short-pedicelled, the pedicels hardly elongating during anthesis (Figs. 27, 28).
10a. Leaves above and below with minute stellate-lepidote hairs, drying yellowish-green, with 8-10 pairs of secondary veins; flowers 1.3-1.6 mm in diam. and 1.5-1.8 mm high.
10b. Leaves above with few stellate hairs, especially on the midrib, below densely covered with longer and more branched hairs, usually drying brown, with (10-) 12-17 pairs of secondary veins; flowers larger than 1.6 mm in diam. and 1.8 mm high.
9b. Pedicels elongating gradually during anthesis and of uneven lengths, the oldest up to 4 cm long (Fig. 24a, 26).
11a. Leaves (7-) 9-15 cm broad, the secondary and tertiary veins below clearly visible
12a. Cymes and receptacles with peltate scales, fruiting receptacles smooth.
12b. Cymes and receptacles densely velvety-pubescent, fruiting receptacles long-tuberculate.
11b. Leaves 4.5-7 cm broad, the veins all inconspicuous.
8b. Flowers with 5-10 stamens.
13a. Pedicels elongating gradually during anthesis and of uneven lengths, the oldest up to 2 cm long.
13b. Pedicels hardly elongating during anthesis, 1-7 mm long.
14a. Leaf apex acuminate, the petioles (1-) 2-3 cm long; the male flowers clavate, the tepals forming a dome that more or less completely encloses the stamens, the female flowers flask-shaped, the tepals forming a calyptra that dehisces circumscissily, leaving a truncate scar.
14b. Leaf apex abruptly cuspidate, the petioles 0.5-1 cm long; the male flowers cup-shaped, the female flowers subglobose, in both morphs the tepals reduced to an 0.2-0.3 mm high rim.
5b. Leaf margin dentate, denticulate, crenate, crenulate, serrate,
doubly serrate, serrulate, or very rarely subentire; plants usually dioecious.
15a. Cymes 1-1.8 cm long.
16a. Outer 4 stamens laterally fused, enclosing a smaller inner stamen (Fig. 33 B).
16b. Stamens free.
17a. Leaves above densely covered with long simple or bifid hairs, the margin dentate, doubly dentate or crenate and conspicuously ciliate with hairs up to 3 mm long.
18a. Leaves 12-24 cm broad; the tepals 3-4 mm long.
18b. Leaves 2-5 cm broad; the tepals reduced to a narrow rim.
17b. Leaves above with few short simple, bifid, or stellate hairs, glabrescent, the margin serrulate, but not ciliate.
15b. Cymes at least 2 cm long, commonly 3-5 cm long.
19a. Leaves below with minute peltate scales and stellate-lepidote hairs.
19b. Leaves below with spreading stellate, few-branched, or simple hairs, or glabrous.
20a. Stamens 5-7(-9) (counting in several flowers if at all possible).
21a. Tepals spatulate or oblong, 0.6-4 mm long and up to 1 mm broad; branchlets quadrangular.
22a. Leaves with 9-10 (-13) pairs of secondary veins, below densely covered with minute stellate hairs, the apex long-cuspidate, (1-) 1.5-2 (-3) cm long.
22b. Leaves with 6-9 pairs of secondary veins, below with scarce simple short hairs, the apex acuminate, 0.5-1 cm long.
21b. Tepals triangular or forming a narrow rim around the floral cup; branchlets terete or sometimes flattened below the nodes (if quadrangular then tepals larger than 0.6-4 x 1 mm).
23a. Leaves typically less than 8 cm broad (measuring several leaves and avoiding extremes).
24a. Floral cup 1.5-2.5 mm in diam.; lower leaf surface with minute stellate hairs, the margin flat.
24b. Floral cup 3-5 mm in diam. ; lower leaf surface glabrous except for a few hairs on the mid rib, the margin often revolute.
23b. Leaves broader than 8 cm.
25a. Floral cup with 0.5-0.8 mm long, often pubescent tubercles; leaves 30-65 cm long.
25b. Floral cup lacking tubercles (at least in male flowers); leaves generally shorter than 30-65 cm.
26a. Leaves with (12-) 15-24 (-26) pairs of secondary veins [male specimens of the following species are problematic to distinguish; refer to Fig. 6-9, 16].
27a. Leaves thin and brittle; branchlets very finely pubescent, glabrescent.
27b. Leaves bullate and relatively thick; branchlets spreading stellate-pubescent.
26b. Leaves with (8-) 9-13 (-16) pairs of secondary veins.
28a. Floral cup with few stellate hairs [the species is only known from the Río Palenque area].
28b. Floral cup densely stellate-pubescent.
29a. Tepals 2-3 mm long [species only known from the western Andean slopes].
29b. Tepals 1.5-2.5 mm long [species only known from the eastern Andean slopes].
19b. Stamens 8-20 (-70) (counting in several flowers if at all possible).
30a. Cymes umbel-shaped; stamens c. 20-70.
31a. Leaves 9-15 cm broad and with 16-22 pairs of secondary veins; male floral cup at anthesis 2.5-4 mm in diam., obconical; stamens 20 (-30) [the species is only known from the Chimborazo area].
31b. Leaves 2.5-7.5 cm broad and with 10-17 pairs of secondary veins; male floral cup at anthesis 6-8 (-10) mm in diam. and 2-3 (-4) mm high, cup-shaped (Fig. 4a, Pl. 3); stamens (20-) 50-70.
30b. Cymes not umbellate; stamens 8-17(-20).
32a. Floral roof stellate-pubescent.
32b. Floral roof glabrous.
33a. Branchlets distinctly flattened at the nodes.
33b. Branchlets terete or quadrangular.
34a. Floral cup with minute tubercles, 0.2-0.3 mm long.
34b. Male floral cup lacking tubercles.
35a. Leaves with 9-13 pairs of secondary veins.
36a. Floral cup 1.3-1.7 mm in diam.; cymes 4-8 cm long.
36b. Floral cup 2-4 mm in diam.; cymes 2-4 cm long.
35b. Leaves with 12-19 pairs of secondary veins.
37a. Floral cup 3-4.5 mm in diam., tepals 1.3-1.5 mm long.
37b. Floral cup 2.3-2.5 mm in diam., tepals 0.5-1 mm long.
Key to Specimens with Female Flowers
1a. Leaf margin entire; plants usually monoecious.
2a. Mature flowers and fruiting receptacles with tubercles, 1-4 mm long.
3a. Branchlets and leaves with minute peltate scales.
3b. Branchlets and leaves with stellate hairs, lacking peltate scales.
4a. Cymes and receptacles densely stellate-pubescent; fruiting receptacles with tubercles 1-2 mm long.
4b. Cymes and receptacles minutely puberulous; fruiting receptacles with tubercles 3-4 mm long.
2b. Mature flowers and fruiting receptacles lacking tubercles.
5a. Female flowers flask-shaped, the tepals forming a calyptra that dehisces circumscissily, leaving a truncate scar at the top of the receptacle, the floral roof acute.
5b. Female flowers subglobose, the tepals forming an upright rim or a dome around the floral roof or rarely free and then acutely triangular.
6a. Leaves in whorls of 4 or 6.
6b. Leaves opposite.
7a. Cymes in subsessile clusters, 1-1.5 cm long.
8a. Tepals minute, about 0.5 mm long.
8b. Tepals 2-3.5 mm long.
7b. Cymes at least 2 cm long, commonly 3-4 cm or longer.
9a. Flowers short-pedicelled, the pedicels hardly elongating during anthesis (Fig. 27); leaves with minute stellate-lepidote hairs, drying yellowish-green.
9b. Pedicels elongating gradually during anthesis, the oldest up to 4 cm long (Fig. 24a, 26); leaves glabrous, drying greyish- or reddish-brown.
10a. Leaves 4.5-7 cm broad, the veins all inconspicuous.
10b. Leaves (7-) 9-15 cm broad, the secondary and tertiary veins below
conspicuously raised.
1b. Leaf margin dentate, denticulate, crenate, crenulate, serrate, doubly serrate, serrulate, or very rarely subentire; plants usually dioecious.
11a. Leaves ascending, the petioles 0.2-0.5 cm long, the lamina 5-6 (-8) cm
long and 2.5-3 (-4) cm broad.
11b. Leaves spreading or drooping, the petioles longer than 0.5 cm, the lamina larger than the above.
12a. Floral cups with spines or tubercles, these minute in young flowers but conspicuous in fruiting specimens (Figs. 1 B, 2 C, 3 A, 4a B, Pl. 2).
13a. Leaves 2.5-7.5 cm broad.
13b. Leaves at least 8-24 cm broad.
14a. Styles 4-6.
15a. Leaves 13-32 cm long, typically elliptic; floral cup 3-3.5 mm in diam.
15b. Leaves 30-65 cm long, oblanceolate; floral cup 4.5-5.5 mm in diam. 2. S. guajalitensis
14b. Styles 7-12.
16a. Leaves lanceolate, 9-15 cm broad.
16b. Leaves elliptic, broadly elliptic to orbiculate, (10-) 15-24 cm broad. 6. S. Croatii
12b. Floral cups lacking elongate tubercles.
17a. Young branchlets, floral cups, and lower leaf surface densely lepidote, without spreading hairs.
17b. Young branchlets, floral cups, and lower leaf surfaces spreading or appressed pubescent, but not exclusively lepidote.
18a. Tepals spatulate or oblong, 0.6-4 mm long and up to 1 mm broad; branchlets quadrangular.
19a. Leaves with 9-10 (-13) pairs of secondary veins, below with dense minute stellate hairs, the apex long-cuspidate, (1-) 1.5-2 (-3) cm long.
19b. Leaves with 6-9 pairs of secondary veins, below with scarce simple short hairs, the apex acuminate, 0.5-1 cm long.
18b. Tepals triangular or forming a narrow rim around the floral cup; branchlets terete or sometimes flattened below the nodes (if quadrangular then tepals larger than 0.6-4 mm x 1 mm).
20a. Cymes 1-1.8 cm long.
21a. Leaves above densely covered with long simple or bifid hairs, the margin dentate, doubly dentate or crenate and usually conspicuously ciliate with hairs up to 3 mm long.
22a. Leaves 12-24 cm broad; tepals 3-4 mm long.
22b. Leaves 2-5 cm broad; the tepals reduced to a narrow rim.
21b. Leaves above with few short simple, bifid, or stellate hairs, glabrescent, the margin serrulate, but not ciliate.
23a. Styles 8-15, the floral roof glabrous.
23b. Styles 15-20 (-30), the tepal rim and floral roof stellate-pubescent.
20b. Cymes at least 2 cm long, commonly 3-5 cm long.
24a. Floral roof stellate-pubescent.
24b. Floral roof glabrous.
25a. Leaves broader than 10 cm (measuring several leaves and avoiding extremes).
26a. Styles 5-8, the flowers 1.5-1.8 in diam. and 1.3-1.5 mm high.
26b. Styles 10-30, the flowers larger than the above.
27a. Young branchlets distinctly flattened; tepals broadly triangular, 1-1.2 mm long.
27b. Young branchlets terete or quadrangular; tepals narrowly triangular, 1.5-7 mm long, or forming a narrow, shallowly lobed rim, but then branchlets terete (S. palenquensis).
28a. Leaves with (12-) 16-20 (-26) pairs of secondary veins; fruiting receptacles distinctly obovoid due to the pedicel becoming thickened [the following species are difficult to distinguish; always refer to their illustrations] .
28b. Leaves with 8-13 (-15) pairs of secondary veins; fruiting receptacles globose, the pedicels barely thickened.
29a. Styles 10-14.
29b. Styles 15-30.
30a. Tepals triangular, 2.5-3.5 mm long.
30b. Tepals forming a narrow, shallowly lobed rim.
25b. Leaves up to 10 cm broad (measuring several leaves and avoiding extremes).
31a. Flowers 1.5-1.8 in diam. and 1.3-1.5 mm high.
31b. Flowers larger than the above.
32a. Styles 4-8.
33a. Leaves acuminate, the tip up to 1 cm long, below with spreading stellate and stellate-lepidote hairs.
33a. Leaves with a distinct drip tip, 2-2.5 cm long, below with minute appressed stellate hairs. 19. S. subscandens
32b. Styles 8-20.
34a. Floral cup 1.5-2.5 mm in diam. ; lower leaf surface with minute stellate hairs.
34b. Floral cup 2-5 mm in diam. ; lower leaf surface essentially glabrous except for a few hairs on the midrib.
Female specimens of the following two species are difficult to distinguish; refer to Figs. 14 and 15 and try to find matching staminate material.
35a. Stamens (7-) 8-14.
35b. Stamens 5-6 (-7).
