Sebastiania pavoniana

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Sebastiania pavoniana
Mexican jumping-bean (4697560519) .gif

Sebastiania pavoniana

Systematics
Eurosiden I
Order : Malpighiales (Malpighiales)
Family : Spurge Family (Euphorbiaceae)
Subfamily : Euphorbioideae
Genre : Sebastiania
Type : Sebastiania pavoniana
Scientific name
Sebastiania pavoniana
( Garbage.Arg. ) Garbage.Arg.
illustration
Spring bean moth ( Cydia deshaisiana )

Sebastiania pavoniana is a species of plant that belongs to the milkweed family(Euphorbiaceae).

The fruits are often inhabited by the larvae of the small butterfly Cydia deshaisiana , which cause a phenomenon of hopping in the individual fruit segments. This has made them known under the name jumping beans or jumping beans .

description

Sebastiania pavoniana is a shrub that grows to heights of around 3 to 6 meters or a tree that becomes over 10 meters high. It has a grayish to coffee-brown bark . The plant contains a white to yellow milky sap , which is highly poisonous and was used by the Indians of Mexico as an arrow poison .

The simple, mostly alternate, hard-leaved, 5 to 11 centimeters long, 2–4.5 centimeters wide, short-stalked, thin, bare leaves have a finely sawn leaf edge. They are ovate to lanceolate, less often obovate or lanceolate, elliptical and at the tip they are rounded to pointed, less often rounded to indented. There are minimal, often sloping stipules . The short petioles are up to 1–1.5 inches long and glands may be present.

Sebastiania pavoniana is monoecious . The very small yellow-green, unisexual flowers, only about 1 millimeter in diameter, have short, usually mixed and slender spikes at the ends of the branches. Very small, little-flowered, purely female inflorescences can occur. The flowers have a simple perimeter , the petals are missing. The male, short-stalked flowers have 2-3 stamens and a three-part perianth . The almost sessile female, somewhat larger flowers have a three-part perianth and an ovary with long, curved, often rolled up stigma branches . The few female flowers per inflorescence are in the lower part and are each underlaid by a bract . Two to three male flowers are each on a bract.

The first green, then coffee-brown when ripe, spherical, weakly three-lobed, smooth capsule fruits are three-part, -faced, have a diameter of 10 to 15 mm and contain a seed in each two-lobed compartment. The blackish, egg-shaped and somewhat speckled, smooth seeds have a small caruncula .

The species is quite widespread in Mexico and also occurs in an area that is off the main area in the province of Guanacaste in northwest Costa Rica .

Jumping beans

Capsule segments (jumping beans) each 7 to 10 millimeters long

When heated, for example when one takes a capsule segment (the jumping bean) in hand, the larva of the jumping bean moth ( Cydia deshaisiana ) living in it begins to twitch so violently that the entire capsule segment moves jerkily.

The law of maintaining the common center of gravity is not violated by this, because the still resting capsule segment, while the larva is accelerating upwards, exerts more force on its base than the weight of the capsule segment and larva. When the larva hits the top of the cavity in the capsule segment, it takes a small piece with it from the approximately four times heavier capsule segment.

The biological meaning of this behavior lies in the fact that the larva and its food try to move from the sun into the shade in order to avoid overheating.

literature

  • Fiediana. No. 36, Flora Costaricensis, 1995, pp. 38, 155 ff, online at biodiversitylibrary.org.
  • Forrest Shreve, Ira L. Wiggins: Vegetation and Flora of the Sonoran Desert. Volume One, Stanford Univ. Press, 1964, ISBN 0-8047-0163-6 , p. 807.

Web links

Commons : Sebastiania pavoniana  - collection of images, videos and audio files

Individual evidence

  1. under 4. Exactly What Are Mexican Jumping Beans? at Palomar College.
  2. Cydia deshaisiana at idtools.org.
  3. Springbohnen Lifecycle on springbohnen.com.