Hot answers tagged

63

It's a matter of perspective. Most of the chemicals that are addictive to us humans (particularly alkaloids), and may be addictive for some other animals as well, are also insecticides. Lots of plants that we consider poisonous are good food for other species, and lots of plants that insects would consider poisonous are treats for us. This is a great ...


55

The phenomenon in question is probably related to geotropism. If the hill soil is "on the move" it will cause the bend on the trees - If the soil in a slope is moving downward, the trees on this slope will tip downward. As the tree continues to try to grow upward, the trunk will show a curve. The degree of bending could indicate the rate or ...


53

The three "holes" are the result of the 3 carpels in coconut flowers, and three carpels is typical of the family Arecaceae (Palms). The "holes" are actually germination pores, where one is usually functional and the other two are plugged. The new coconunt shoot will emerge from the functional, open, germination pore (see this webpage for pictures and further ...


33

That molecule is called Geosmin. It is mainly produced 1 by Actinomycetes such as Streptomyces which are filamentous bacteria that live in soil. Other organisms also produce geosmin: Cyanobacteria Certain fungi An amoeba called Vanella A liverwort It is an intracellular metabolite and cell damage is the primary reason attributed to its release. However ...


27

As someone commented earlier, chemicals such as nicotine and morphine were products of evolution meant to repel animals. It is explained in more details in this article here. Evolutionary biologists studying plant–herbivore interactions have convincingly argued that many plant secondary metabolites, including alkaloids such as nicotine, morphine and ...


25

The use of a genus-species notation gives more exact information. For example there are multiple species of chamomile: There is Roman chamomile (Chamaemelum nobile), German chamomile (Matricaria recutita, or Chamomilla recutita) and Dyer's chamomile (Anthemis tinctora). The first two species are appraised for their medicinal properties and help to calm upset ...


13

It looks like a "Spider lily" from the Hymenocallis genus. Here is a picture of Hymenocallis caribaea from wikipedia for comparison: There are however ~65 species in the genus (according to wikipedia), and I cannot say exactly what species you have.


11

I am providing an example which somewhat contradicts the points mentioned in the other answers regarding toxicity of alkaloids to insects. Caffeine is a stimulant and is toxic at high doses (also for humans) but at low doses it has a stimulating pharmacological effect on the organism. The same principle applies to insects as well. A study by Wright et. al (...


11

This is actually not a gall as other answers have suggested. This is likely a fungus called Cedar-apple rust (Gymnosporangium juniperi-virginianae). The fungus only thrives in the presence of both Juniperus virginiana (Eastern red cedar) and apple (Malus spp.) trees. The leaf in the picture belongs to some species of the apple genus and the growths are ...


11

Short answer Plants release O2, because it is not an energy source. Instead, it is used to free energy from energy-rich organic compounds. Background Plants are solar powered. They release oxygen as a waste product during carbon fixation. Carbon fixation is basically the storage of solar power into carbon-bonds in glucose, a process referred to as ...


10

First it needs to be said that coconut trees are not true trees, but palms, whose trunks are made of stems which grow in a cross woven pattern. That being said - its true for any plant that no plant grows from the bottom up. If you make a mark on any plant that mark will not rise much as the plant grows. Plants grow from buds at the end of their stems. ...


9

The Latin names are known in all countries. The "popular" names are only popular in one or maybe two languages/countries. So, learning the Latin names, enables you to communicate international more easily.


9

The two commonly put-forward explanations for spiral growth of tree trunks related to stress-loading and damage-tolerance. The stress-loading explanation states that spiral-grained trees flex more than straight-grained trees before they break. Flexibility under stress-loading is useful in areas with heavy snowfall (as the tree can flex until the snow falls ...


9

Those are the fruit clusters of a common "wildflower" that often grow in wet areas, called Eastern Skunk Cabbage or Symplocarpus foetidus. Initially (early Spring), it's not bad looking (and some species - such as the western skunk flower - are even pretty): But after a while, the spathe (sheath) dries up while the seeds grow in the spadix (the ...


9

This is a female of yet another scale insect (Coccoidea). We have discussed one recently. I guess we can identify this one rather precisely as Ceroplastes sinensis or its close relative. Species of this group are of South American origin, but Ceroplastes sinensis has today an extremely broad distribution. So, if you found this plant ("Variegata" is a ...


8

The tree in question belongs to the Araucariaceae family, There are multiple species of Genus Araucaria, I'd place Araucaria araucana on the first place, but there are multiple others: Araucaria araucana Araucaria luxurians Araucaria columnaris Araucaria subulata


8

It looks very similar to Cephalaria gigantea.


8

It generally won't be more helpful. Not only will the names be different in different countries, there may be different types of the same species with different properties, or even different species with the same common name. If you have an allergy to something like coriander, being able to read the label and see what contains actual coriander and what ...


8

They are either treated or even declared to be synonyms in all the texts using both of the terms that I have ever read. Just one reference: the nearest Flora on my desk, G. Marconi, F. Corbetta, Flora della Pianura Padana e dell'Appennino Settentrionale, uses the notation Compositae = Asteraceae. It is worth to note that Compositae, 'composite ones' in ...


8

If you do a Google Image search with the picture in the question, you'll see the screenshot is from the 2000 movie The Patriot starring Mel Gibson. The movie's filming locations were mainly scattered around South Carolina, on the southern East Coast of the United States. I've spent a lot of time in the region, and the gray-ish fluffy stuff hanging off the ...


7

Short answer The appearance of psychoactive compounds in plants has nothing to do with their addictiveness in man. Background Psychoactive plants were there long before humans. The question therefore should be: "Why would humans evolve brains that exhibit addictive propensity to poisonous compounds abundantly available in nature"? The answer is: because our ...


7

From the link given by @Kendall Such a gradient can be maintained because the thylakoid membrane is essentially impermeable to protons. I think this solves your dilemma of 'why not maintaining equilibrium' totally. The reason for this difference is that the thylakoid membrane is quite permeable to Cl- and Mg2+. The light-induced transfer of H+ ...


7

Many ornamental cherries are grown on a hardier root stock, that is, they are propagated by grafting onto hardy wild cherry saplings. This is because the ornamental variety will not produce offspring that are true to the parents, if they produce offspring at all. All are grafted plants and mainly on wild cherry (gean) rootstock. Such trees should be ...


7

It looks like sustained or consistent moisture might be (at least part of) the phenological cue for flowering: The wikipedia article mentions that consistent humidity will induce flowering in at least some species and cites Fernández-Alonso & Groenendijk (2004), which says: It generally flowers after the rainy periods, but in humid pastures and ...


6

It appears to me to be a Night Blooming Cereus: We had one in our greenhouse in Botany. It rarely bloomed, and the bloom was wilted by mid-morning. Night-blooming cereus is the common name referring to a large number of flowering ceroid cacti that bloom at night. The flowers are short lived, and some of these species, such as Selenicereus grandiflorus,...


6

Excellent question! The main reason why us humans bury seeds seems to be to keep seed-eaters from finding them, though any historical evidence that could conclusively prove why we started doing that is probably lost to time, since we discovered agriculture before we began writing things down. Beyond that, you've rightly identified a number of advantages to ...


6

It looks like a Red Campion, which is native to northern and central Europe. It would be nice to see a close-up of the calyx (which is usually striped) and the leaves to be sure; it may be a cross between a White and Red Campion. There are many members of the genus, and many look alike. Your close-up is of a male flower (anthers only). The plants are ...


5

You originally posted this question on the Garden and Landscaping Section - that's where I'm from, and though it was moved here instead, I'll answer it anyway: That image you've shown isn't like a photograph, its an impression of what the roots are like. Usual method of working out root patterns on plants is to remove what's known as a monolith, or a block ...


5

I think it is a common stinging nettle, Urtica dioica. It is a native to Europe, Asia, northern Africa, and western North America and is the best-known member of the nettle genus Urtica. As commented by others, your geographical location would be helpful to obtain a more accurate identification. Like other stinging nettles, it is unpleasant to the touch, ...


5

So what's going on here? Personally speaking, I don't think the tomato is anything like the pomegranate. However, generally speaking the appearance of similar traits despite widely divergent ancestry is called Convergent Evolution. Some traits -- let's say round fruit and red coloring -- may be so advantageous that they evolved multiple different times ...



Only top voted, non community-wiki answers of a minimum length are eligible