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 ...


14

The plant is of Lamiaceae family and its common name is Shell Flower or Bells of Ireland. Its "scientific" aka latin name is Moluccella laevis.


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

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

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

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

Yes, it is possible, but not necessarily the case. Non-green leaves with chlorophyl: There are leaves that don't appear green, but do have chlorophyl and therefore can conduct photosynthesis. (See, for instance, refraction effects in white caladiums or the link in the answer by Resonating). Non-green leaves without chlorophyl: There are leaves that don't ...


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

As @dd3 stated, it's a spiny (or prickly) sow thistle. It's an annual common in most of the US. The leaf itself does not have a stem, and if you break the central stalk, it should be hollow and there should be a milky exudate. The plant spreads by fluffy seeds produced from a small dandelion-like flower. If you pick it while young, it won't hurt (as much); ...


8

It's a bit early yet, but it looks very much like a weed known in my area as "cleavers" or "clingweed" (Galium aparine) because of it's tiny stiff hairs which make it catch and cling to clothing. The picture below is for a fully mature plant, which is stiffer and stickier than when they first sprout. Note the whorl arrangement of (usually six) leaves, with ...


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 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

It looks very similar to Cephalaria gigantea.


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

The University of California, LA mentions some genera and species of salt-loving plants (halophytes): The genus Atriplex (Family Chenopodiaceae), saltbush, is found worldwide along saline shorelines. On the surfaces of the leaf are vesiculated trichomes (hairs). Each trichome has a stalk and a balloon-like tip, the bladder cell. The leaves use the bladder ...


7

Those are known as Rhododendrons, and I'd ID that one as R. hodgsonii.


7

One thing to remember when you uproot a plant is that some of the smallest structures break off most readily. What you will usually see after uprooting the plant are the largest parts of the root structure, but there are often smaller parts which have broken off. Root structure is highly variable, but the general idea is that one or more primary trunk-like ...


7

Looks like a Hyoscyamus niger also called stinking nightshade.


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+ ...



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