Croton monanthogynus Michx.

One-Seeded Croton

Croton monanthogynus plant

Family - Euphorbiaceae

Stems - To +/-30cm tall, erect, from fibrous roots, divaricately branching (forming a small tree-like plant), stellate pubescent, slightly woody at the base. Stellate hairs with a purplish center (attachment point).

Croton monanthogynus stem

Leaves - Alternate, petiolate. Petioles to 2cm long, pubescent as the stem. Blades ovate to lanceolate, to +4cm long, -2.5cm broad, entire, acute, stellate pubescent adaxially, densely stellate pubescent abaxially (the hairs with a white center).

Croton monanthogynus leavesPressed leaves.

Croton monanthogynus leafAbaxial surface of the leaf close-up. Note the stellate hairs.

Inflorescence - Axillary androgynous racemes to 1cm tall, with typically 2-3 staminate flowers and 2-3 pistillate flowers. The axis densely stellate pubescent. Pedicels of staminate flowers to 1.5mm long. Pedicels of pistillate flowers 1mm long. All pedicels densely stellate pubescent, elongating in fruit.

Flowers - Staminate - Petals 4, spreading, white, 1.3mm long, .7mm broad, ciliate-margined at the base, oblong-elliptic. Stamens 6(3-8), erect to spreading. Filaments white, 1.4mm long, glabrous. Anthers white, .6mm broad. Sepals 4, ovate, 1.2mm long, 1mm broad, stellate pubescent abaxially, glabrous adaxially, white. Pistillate flowers - Sepals 5, linear-oblong, spreading, dense stellate pubescent, green, acute, +2mm long, -1mm broad, accrescent. Ovary superior, globose-ovoid, densely stellate, green, 1.1mm long and broad. Styles 2, deeply divided and appearing as 4, to 1.1mm long, linear, spreading to erect, densely stellate pubescent.

Croton monanthogynus staminate flowersStaminate flowers.

Croton monanthogynus pistillate flowerPistillate flower.

Fruits - Fruits one-seeded, with persistent styles. Seeds black, 3mm in diameter, lenticular.

Croton monanthogynus pistillate fruitYoung fruits.

Flowering - May - September.

Habitat - Typically on acid soils overlying chert, sandstone, or granite substrata. Glades, upland prairies, open and waste ground, roadsides, railroads.

Origin - Native to U.S.

Other info. - This little species can be found throughout Missouri but is less common in the extreme north-central portion of the state. The plant is small but resembles a small tree because of its widely spreading branches. This species and another, C. capitatus Michx., appear similar at first but there are distinct differences between the two species which makes them easily distinguished in the field. C. monanthogynus is the only Missouri croton which has two split styles for a total of 4 stigmatic branches.
The plant is toxic to some species of animals but apparently tolerated by others.

Photographs taken at Logan Creek, Reynolds County, MO., 7-6-03 (DETenaglia); also near Dutzow, Warren County, MO, 7-23-2016 (SRTurner).


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