# What plants can't reproduce without human assistance? **URL:** \ **Category:** Factual Questions\ **Created:** [January 20, 2011, 1:22pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316 "2011-01-20T13:22:51Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Aspidistra](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aspidistra/32/3894_2.png) [@Aspidistra](https://boards.straightdope.com/u/Aspidistra)\ **Post date:** [January 20, 2011, 1:22pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/1 "2011-01-20T13:22:51Z")
I’m pretty sure bananas can’t. From the wikipedia page: > [@](#): > > Cultivated bananas are parthenocarpic, which makes them sterile and unable to produce viable seeds. Lacking seeds, propagation typically involves removing and transplanting part of the underground stem (called a corm). Anything else? ---
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [January 20, 2011, 1:38pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/2 "2011-01-20T13:38:36Z")
Note that this cite doesn’t speak about bananas in general, only about cultivated bananas. Many of the cultivated seedless breeds can’t reproduce without human intervention, precisely because they are seedless - rather, each generation has to be bred or transplanted anew. But these breeds have specifically been created by humans; wild bananas can and do, of course, reproduce without human intervention. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [January 20, 2011, 1:58pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/3 "2011-01-20T13:58:34Z")
Corn, _zea mays_, can not reproduce on its own. The ears are too tightly wrapped with leaves for the seeds to get out on their own. ---
**Author:** ![DrFidelius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drfidelius/32/3447_2.png) [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)\ **Post date:** [January 20, 2011, 2:01pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/4 "2011-01-20T14:01:58Z")
Most cultivars require intervention to reproduce. That’s part of cultivation. ---
**Author:** ![Ionizer](https://avatars.discourse-cdn.com/v4/letter/i/5daacb/32.png) [@Ionizer](https://boards.straightdope.com/u/Ionizer)\ **Post date:** [January 20, 2011, 2:32pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/5 "2011-01-20T14:32:30Z")
> [@Broomstick](#): > > Corn, _zea mays_, can not reproduce on its own. The ears are too tightly wrapped with leaves for the seeds to get out on their own. I challenge this heartily. [According to USDA](http://plants.usda.gov/java/profile?symbol=ZEMA), it is/can be weedy/invasive (!) Who would be going around tossing the unwrapped seed to produce this classification? Are you saying that the very first corn ear had a person there to unwrap it so it could grow again? And repeat every year for how many centuries/eons? I toss my ‘bad corn ears’ (bug infested or just not worth husking) into a pile every year, and I _always_ get corn sprouts the next year from the pile. I do not bother to husk the ears before tossing 😉 Both Silver Queen and Peaches & Cream varieties have germinated a few sprouts minimum the next year without me unwrapping ‘em at all, so I am sure that plain ol’ corn would do so as well. Animals/insects might help unwrap the ears, but it does not require _humans_ in any way (unless a specific cultivar is intent, which requires controlled pollination usually). There are many ‘cultivars’ that require being cloned to continue the lineage since the seed does not form well enough to carry the genes to next generation. As example, seed from a Winesap apple generally won’t grow a Winesap apple - probably would grow more as a crabapple-type apple. Cloning by cuttings, germ tissue, grafting, etc is how cultivars are kept from reverting (usually). ‘Basic’ varieties just keep on reproducing as Nature designed 'em to do. ---
**Author:** ![Dr.Drake](https://avatars.discourse-cdn.com/v4/letter/d/ad7895/32.png) [@Dr.Drake](https://boards.straightdope.com/u/Dr.Drake)\ **Post date:** [January 20, 2011, 2:40pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/6 "2011-01-20T14:40:13Z")
The bergamot ([http://en.wikipedia.org/wiki/Bergamot\_orange](http://en.wikipedia.org/wiki/Bergamot_orange)) doesn’t even exist as an independent plant, only as a graft onto other citrus stock. I’m sure there are many varieties of cultivated fruit for which that is the case. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [January 20, 2011, 4:01pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/7 "2011-01-20T16:01:31Z")
> [@Ionizer](#): > > I challenge this heartily. [According to USDA](http://plants.usda.gov/java/profile?symbol=ZEMA), it is/can be weedy/invasive (!) I’m not sure what the basis of that classification might be. Certainly I’ve never known it to be weedy or invasive; I suspect this circumstance must be very rare if it occurs. Domestic corn is very frequently stated to be incapable of reproducing itself in the wild to any great extent. This is not only due to the tight husks, but also because the kernels adhere strongly to the ear and do not easily disarticulate. Whether or not domestic corn might not occasionally reproduce in the wild, it is very poorly suited to disperse its seeds. > [@](#): > > Who would be going around tossing the unwrapped seed to produce this classification? If wild reproduction occasionally occurs, I expect it is either because of spilled grain or because the ears have been opened and the seeds dispersed by animals. > [@](#): > > Are you saying that the very first corn ear had a person there to unwrap it so it could grow again? This is certainly the case. Maize as we know it is unknown in the wild; the first evidence of it is as an agricultural plant. For a long time its origin was a great mystery, exactly because its characteristics make it unsuitable for propagation without human assistance. It is know generally acknowledged to be descended, through hybridization (and perhaps with additional mutations) from various forms of [teosinte](http://en.wikipedia.org/wiki/Teosinte), though even now the details are controversial. ---
**Author:** ![Markxxx](https://avatars.discourse-cdn.com/v4/letter/m/5daacb/32.png) [@Markxxx](https://boards.straightdope.com/u/Markxxx)\ **Post date:** [January 20, 2011, 4:12pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/8 "2011-01-20T16:12:34Z")
Wow I never thought about it, but bananas have to be involved in a three-way (at least) to reproduce 🙂 ---
**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\ **Post date:** [January 20, 2011, 4:46pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/9 "2011-01-20T16:46:30Z")
Navel oranges. ---
**Author:** ![Tapioca\_Dextrin](https://avatars.discourse-cdn.com/v4/letter/t/3d9bf3/32.png) [@Tapioca\_Dextrin](https://boards.straightdope.com/u/Tapioca_Dextrin)\ **Post date:** [January 20, 2011, 4:58pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/10 "2011-01-20T16:58:27Z")
[Seedless grapes and melons](http://www.straightdope.com/columns/read/1075/how-do-they-grow-more-seedless-fruit). ---
**Author:** ![aruvqan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aruvqan/32/2891_2.png) [@aruvqan](https://boards.straightdope.com/u/aruvqan)\ **Post date:** [January 20, 2011, 6:23pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/11 "2011-01-20T18:23:15Z")
> [@Broomstick](#): > > Corn, _zea mays_, can not reproduce on its own. The ears are too tightly wrapped with leaves for the seeds to get out on their own. Then what explains the random rogue corn growing in the woods on my place [and we haven’t planted corn in about 15 years so it has to come from one of the farmers on the road] ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [January 20, 2011, 6:23pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/12 "2011-01-20T18:23:36Z")
> [@Dr.Drake](#): > > The bergamot ([http://en.wikipedia.org/wiki/Bergamot\_orange](http://en.wikipedia.org/wiki/Bergamot_orange)) doesn’t even exist as an independent plant, only as a graft onto other citrus stock. I’m sure there are many varieties of cultivated fruit for which that is the case. Do you have a source for this? The Wiki article doesn’t mention it and [Bergamot Orange - Citrus aurantium ssp bergamia](http://www.tradewindsfruit.com/bergamot.htm) says “Propagation: Commonly by seed which usually produce trees very near in fruit quality to their parent. Also by grafts.” But aren’t almost all wine and eating grapes grown by grafts onto rootstock of American concord grapes (a different species)? ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [January 20, 2011, 6:40pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/13 "2011-01-20T18:40:40Z")
> [@Ionizer](#): > > I challenge this heartily. [According to USDA](http://plants.usda.gov/java/profile?symbol=ZEMA), it is/can be weedy/invasive (!) Who would be going around tossing the unwrapped seed to produce this classification? Are you saying that the very first corn ear had a person there to unwrap it so it could grow again? And repeat every year for how many centuries/eons? I toss my ‘bad corn ears’ (bug infested or just not worth husking) into a pile every year, and I _always_ get corn sprouts the next year from the pile. I do not bother to husk the ears before tossing 😉 Both Silver Queen and Peaches & Cream varieties have germinated a few sprouts minimum the next year without me unwrapping ‘em at all, so I am sure that plain ol’ corn would do so as well. Animals/insects might help unwrap the ears, but it does not require _humans_ in any way (unless a specific cultivar is intent, which requires controlled pollination usually). > > There are many ‘cultivars’ that require being cloned to continue the lineage since the seed does not form well enough to carry the genes to next generation. As example, seed from a Winesap apple generally won’t grow a Winesap apple - probably would grow more as a crabapple-type apple. Cloning by cuttings, germ tissue, grafting, etc is how cultivars are kept from reverting (usually). ‘Basic’ varieties just keep on reproducing as Nature designed 'em to do. IIRC, the Scientific American article that traced he evolution of corn as a staple crop in the south USA/Mexico area mentioned that it could not grow in the wild. Obvioulsy seeds properly placed will grow, and being trapped in the husk does not seem to stop most of them; but unless someone/something makes a point of hauling the ears around, it seem to me they sit where they grow. Maybe you get fairy rings of corn? The article also traced the gradual evolution through selective cultivation - from a grass head with tiny kernels that spread in the wild just fine to progressively bigger and more tightly wrapped ears that did not disperse naturally. SO the question is - does the local animal population present enough of a dispersal mechanism to let corn spread without human intervention? ---
**Author:** ![Dr.Drake](https://avatars.discourse-cdn.com/v4/letter/d/ad7895/32.png) [@Dr.Drake](https://boards.straightdope.com/u/Dr.Drake)\ **Post date:** [January 20, 2011, 6:50pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/14 "2011-01-20T18:50:13Z")
> [@Quercus](#): > > Do you have a source for this? The Wiki article doesn’t mention it and [Bergamot Orange - Citrus aurantium ssp bergamia](http://www.tradewindsfruit.com/bergamot.htm) says “Propagation: Commonly by seed which usually produce trees very near in fruit quality to their parent. Also by grafts.” > But aren’t almost all wine and eating grapes grown by grafts onto rootstock of American concord grapes (a different species)? No authoritative source; I was told this by a bergamot farmer in Italy. Looking around online, I find [http://www.agraria.org/coltivazioniarboree/coltivazioneagrumi.htm](http://www.agraria.org/coltivazioniarboree/coltivazioneagrumi.htm) which says “Per prevenire alcune fitopatie che colpiscono l’apparato radicale si ricorre all’innesto” [“In order to prevent any of the diseases that attack the root system they resort to grafting”]. Elsewhere it says that the seeds are monoembryonic, which I gather has something to do with this. So apparently I was misinformed about their ability to grow from seeds, even if in practice it doesn’t much happen. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [January 20, 2011, 6:56pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/15 "2011-01-20T18:56:42Z")
> [@Ionizer](#): > > I challenge this heartily. [According to USDA](http://plants.usda.gov/java/profile?symbol=ZEMA), it is/can be weedy/invasive (!) Who would be going around tossing the unwrapped seed to produce this classification? During corn harvesting it is entirely possible for seed to drop on the ground during processing. I suppose it is also possible for foraging animals to leave a few seeds behind and _not_ have those seeds subsequently snatched by other animals. > [@](#): > > Are you saying that the very first corn ear had a person there to unwrap it so it could grow again? Yep. Modern corn is so far removed from its wild ancestor that it wasn’t until we could analyze complete genomes that scientists could finally say with confidence that _Zea mays_ is a descendant of teosinte. Corn was created by centuries of selective breeding by humans and the intermediate forms between teosinte and _Zea mays_ have all been lost. Corn as we know it is entirely the product of human intervention. > [@](#): > > ‘Basic’ varieties just keep on reproducing as Nature designed 'em to do. Sure - but _Zea mays_ isn’t a natural creation, it’s a human production. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [January 20, 2011, 6:59pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/16 "2011-01-20T18:59:34Z")
> [@Quercus](#): > > But aren’t almost all wine and eating grapes grown by grafts onto rootstock of American concord grapes (a different species)? Yes, but that is because of a disease imported from North America to Europe, not because European grapes are incapable of reproducing. The problem is that once they reproduce they have no resistance to the invasive pest ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [January 20, 2011, 7:01pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/17 "2011-01-20T19:01:30Z")
> [@aruvqan](#): > > Then what explains the random rogue corn growing in the woods on my place [and we haven’t planted corn in about 15 years so it has to come from one of the farmers on the road] Could be dropped kernels during harvest, processing, or transport. Also some random transport by animals. It’s not that corn _never_ pops up the next year - I see random stalks in soybean fields all the time around here - it’s just that it’s so very inefficient at dispersal that no population is going _survive_ in the wild without human activity. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 20, 2011, 7:34pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/18 "2011-01-20T19:34:26Z")
Many plants with ‘double’ flowers lack essential reproductive organs and cannot therefore produce viable seed. Some of these can probably still reproduce on their own via suckers (shoots arising from the base or roots, capable of becoming independent plants), natural layering (branches touching ground and taking root), etc. ---
**Author:** ![Kimstu](https://avatars.discourse-cdn.com/v4/letter/k/ecd19e/32.png) [@Kimstu](https://boards.straightdope.com/u/Kimstu)\ **Post date:** [January 20, 2011, 8:09pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/19 "2011-01-20T20:09:41Z")
> [@Broomstick](#): > > It’s not that corn never pops up the next year - I see random stalks in soybean fields all the time around here - it’s just that it’s so very inefficient at dispersal that no population is going survive in the wild without human activity. Yeah, it looks as though we need a clarification of the question in the thread title here. There are plants that literally **cannot** reproduce themselves without physical intervention by humans, as in the case of the seedless/grafted fruits mentioned above; and then there are plants that **can** physically reproduce untouched by humans, but not reliably enough to create sustainable populations, as in the case of maize/corn. ---
**Author:** ![Ionizer](https://avatars.discourse-cdn.com/v4/letter/i/5daacb/32.png) [@Ionizer](https://boards.straightdope.com/u/Ionizer)\ **Post date:** [January 20, 2011, 9:04pm UTC](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316/20 "2011-01-20T21:04:41Z")
I just went and looked out in my ‘trash plants’ pile, and found several germinating corn seed 🙂 It has been warm enough last few weeks or so to cause germination(s) of many things, and the corn is being compliant. Again. This morning’s ice/sleet upon them certainly killed 'em, but they were living quite happily until then apparently. All I did was toss crappy ears atop other stuff to rot compost-style and Nature did the rest. The OP asked about human intervention, and for the third year in a row, corn has popped up without me doing a thing for it. I would call that pretty reliable. Interesting about corn being ‘domesticated’ and not just found in wild and taken/improved from there. Ignorance fought and off I go to read more on it. But I stand firm that it does _not_ require humans to grow/spread on its own. Perhaps climate variances may make a difference in viability or such other than my Zone 7 location (shrug). I know corn won’t grow well at all without a high-nitrogen soil so location makes a difference as well obviously. I have also seen plenty of stray corn growing along canals in south/central Idaho (11+ years ago) that in no way could’ve gotten there by humans unless some person went waaaay way outta their way to plant it (?). Rarely were many stalks present as the cold weather prevented it from getting thick - I _presume_ that killed most seed keeping it from flourishing, and lots of corn was grown commercially along those canals to provide seed to spread by whatever means. Sometimes the canal was in middle of desert with no real roads around for miles nor any farming anywhere near (areas where I went hunting quite often). There was often ‘wild’ asparagus nearby them as well. Oh, I miss that near-unlimited free asparagus really bad nowadays. Reading through a wiki article (and other/better sources too) on corn says that there is much uncertainty of modern corn’s actual origin, so I guess it is fair to say that it is not really known for sure (right?). I will let others fight that part out as it makes no difference to me 🙂 Corn is tasty and I now I want some myself… [Next page](https://boards.straightdope.com/t/what-plants-cant-reproduce-without-human-assistance/568316.md?page=2)