CGP Grey
Published 1 Mar 2020Director’s commentary: https://www.youtube.com/watch?v=rbHQO…
## Crowdfunders:
Bob Kunz, Steven Snow, John Buchan, Nevin Spoljaric, Donal Botkin, Phil Gardner, Chris Chapin, Richard Jenkins, Martin, Steven Grimm, سليمان العقل, Colin Millions, Michael Mrozek, Saki Comandao, Jason Lewandowski, Andrea Di Biagio, David F Watson, rictic, Ben Schwab, Marco Arment, Elliot Lepley, Shantanu Raj, emptymachine, Bobby, Chris Amaris, George Lin, Mikko, Derek Bonner, Derek Jackson, Orbit_Junkie, Ron Bowes, Tómas Árni Jónasson, Henry Ng, Jordan Earls, Joshua Jamison, Nick Fish, Nick Gibson, Robert Webb, Jeffrey Podis, Thunda Plum, Awoo, David Tyler, Fuesu, iulus, Kevin Costello, Michael Reilly, Tyler Bryant, Kermit Norlund, chrysilis, David Palomares, Erik Parasiuk, ken mcfarlane, Leon, Tristan Watts-Willis, Veronica Peshterianu, Bear, Emi, Esteban Santana Santana, Freddi Hørlyck, John Rogers, Maarten van der Blij, Peter Lomax, Rhys Parry, ShiroiYami, Dag Viggo Lokøen, John Lee, Maxime Zielony, Elizabeth Keathley, Frederick The Great, Luxe Gifts, Rebecca Wortham, Bryan McLemore
Music by Music by: http://www.davidreesmusic.com
Wikipedia says:
A tumbleweed is a structural part of the above-ground anatomy of a number of species of plants, a diaspore that, once it is mature and dry, detaches from its root or stem, and rolls due to the force of the wind. In most such species, the tumbleweed is in effect the entire plant apart from the root system, but in other plants, a hollow fruit or an inflorescence might serve the function. Tumbleweed species occur most commonly in steppe and arid ecosystems, where frequent wind and the open environment permit rolling without prohibitive obstruction.
Apart from its primary vascular system and roots, the tissues of the tumbleweed structure are dead; their death is functional because it is necessary for the structure to degrade gradually and fall apart so that its seeds or spores can escape during the tumbling, or germinate after the tumbleweed has come to rest in a wet location. In the latter case, many species of tumbleweed open mechanically, releasing their seeds as they swell when they absorb water.
The tumbleweed diaspore disperses seeds, but the tumbleweed strategy is not limited to the seed plants; some species of spore-bearing cryptogams — such as Selaginella — form tumbleweeds, and some fungi that resemble puffballs dry out, break free of their attachments and are similarly tumbled by the wind, dispersing spores as they go.
[…]
In the family Amaranthaceae (i.e. broadly defined to include Chenopodiaceae), several annual species of the genus Kali are tumbleweeds. They are thought to be native to Eurasia, but when their seeds entered North America in shipments of agricultural seeds, they became naturalized in large areas. In the cinema genre of Westerns, they have long been symbols of frontier areas. Kali tragus is the so-called “Russian thistle”. It is an annual plant that breaks off at the stem base when it dies, and forms a tumbleweed, dispersing its seeds as the wind rolls it along. It is said to have arrived in the United States in shipments of flax seeds to South Dakota, perhaps about 1870. It now is a noxious weed throughout North America, dominating disturbed habitats such as roadsides, cultivated fields, eroded slopes, and arid regions with sparse vegetation. Though it is a troublesome weed, Kali tragus also provides useful livestock forage on arid rangelands.
