Croton spica, Baillon, 1864

Da Silva, Marcos J., Sodré, Rodolfo C. & Berry, Paul E., 2015, An enigmatic species of Croton (Euphorbiaceae) is rediscovered after more than 100 years in midwestern Brazil, Phytotaxa 221 (1), pp. 83-88 : 87

Key to Croton spica and related species

1. Leaf blade with sessile or subsessile patelliform glands in the marginal sinuses; pistillate calyx strongly unequal, accrescent in fruit and with at least two sepals widely obovate to widely elliptic and obtuse or acuminate at the apex .............................................. 2

- Leaf blade with or without stipitate-capitate glands in the marginal sinuses; pistillate calyx with sepals equal or slightly unequal, not accrescent in fruit, ovate to lanceolate and acute at the apex ..................................................................................................... 3

2. Leaf blade with 5–10 pairs of secondary veins, the two basal pairs of veins never reaching halfway up the blade; petiolar glands patelliform, 1–1.2 mm diameter; inflorescences deltoid when young, with 2–5 pistillate flowers distributed along the basal ¼ of the axis; staminate petals lanceolate or linear-oblong; pistillate sepals with margins serrate, the larger two 6–9 mm long; capsule 5–5.5 mm long, globoid to oblongoid; seeds maculate ......................................................................................................... C. spica

- Leaf blade with 2 or 3(–4) pairs of secondary veins, the basal pair of veins surpassing half the length of the blade; petiolar glands patelliform-stipitate, cupuliform or turbinate and 0.35–0.5 mm diameter; inflorescences cylindrical when young, with 9 or more pistillate flowers distributed along more than ½ the length of the axis; staminate petals oblanceolate; pistillate sepals 2.3–4(–5) mm long, margins entire; capsule 3.5–4 mm long, subgloboid; seeds uniformly colored ................................................... C. abaitensis

3. Staminate flowers with 12–15 stamens; pistillate sepals with glands ............................................................................. C. agoensis

- Staminate flowers with 11 stamens; pistillate sepals without glands ............................................................................................... 4

4. Leaf blade with stipitate-capitate glands on the margin; styles glabrous ................................................................ C. mucronifolius

- Leaf blade with or without sessile patelliform glands on the margin; styles pubescent .................................................................. 5

5. Petiole 3–10 mm long, leaf blade with glands on the margin ................................................................................... C. longinervius

- Petiole up to 1.5 mm long, leaf blade without glands on the margin ........................................................................ C. pycnadenius