The study of plant life; e.g. angiosperms, gymnosperms, bryophytes, pteridophytes, and algae.

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Why are neutral [sterile] female flowers present in inflorescences when they are reproductively incompatible?

In many compound and special inflorescences like spadix and hypanthodium there are sterile female flowers along with male and female fertile flowers and are often present in between male and female ...
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2k views

Online course on Plant Taxonomy and Physiology

After following a course in Permaculture, I realised that if I want to get serious about it, I need to be able to distinguish plants. So I am looking for an online Video course on Plant Taxonomy and ...
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465 views

What is the largest perennial herbaceous plant?

What is the largest perennial herbaceous plant? My guess would be some kind of banana or bamboo.
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116 views

Fruit-bearing tree identification

Just moved into a new house in Puerto Rico and I found this tree in the back garden. Can anyone tell me what tree this is, and whether its fruit is edible?
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372 views

Sexual Differentiation in Monoecious plants with unisexual flowers

In monoecious plants having unisexual flowers (eg Zea Mays, Ricinus Communis etc), there must be some mechanism as to produce two sexually distinct flowers from the same genotype. Since both the type ...
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259 views

Function of papain in papaya

I know that papain is a proteolytic enzyme present in papaya. It is often used to tenderise meat. What is the function of papain in papaya? Is papain sweet? Does it function as an antibiotic?
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199 views

Plant identification?

Can anyone identify the plant below? It's in a backyard in Pennsylvania, and the photo was taken today.
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35 views

Determine which seed will germinate first

I recently studied about plant physiology for a test. Strangely, there was this question which I had no idea how to approach. The question is, Which seed will germinate first? a) Castor b) Wheat ...
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54 views

How do I read a species description that uses both ≡ (triple bar) and “incl.” to denote synonymy?

I'm trying to understand the relationship of plants formerly classified as Dorstenia crispa with distinct individuals continuously classified as Dorstenia foetida. I would assume that the distinctive ...
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583 views

Cause of Crease in Drupe Fruit

What causes the crease through the pericarp of a drupe fruit (peach, nectarine, olive)? It may just be in exocarp as @Ilan pointed out, but I assumed (perhaps wrongly), that the division continued ...
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74 views

Why do plants produce so many hybrids as a kingdom?

Why do plants produce so many hybrids? I have read that they are the largest kingdom of organisms to do so. Does this have something to do with polyploidy events?
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180 views

How does Pothos grow in only water?

The popular potted plant, Pothos aureus (or Epipremnum aureum) is happy to grow in a jar, with only water, for years. How is this possible when other plants need at least Nitrogen, Phosphorus and ...
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113 views

Is the water transpired by plants pure H₂O, or does it contain trace minerals?

I'm considering the idea of drinking water that I trap from what is transpired by trees. Interestingly, is this water a fairly (or maybe even extraordinarily) pure form of H₂O, a remarkably pure ...
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130 views

Why do humans circulate monosaccharides instead of disaccharides as in plants?

Plants transport food mostly in the form of disaccharides like sucrose but humans transport them in the form of a monosaccharide - glucose. What is the reason behind this ?
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104 views

H₂S as a source of electrons for plants

The first electron source for plants was H2S, but now most modern plants use H2O as an electron source. What is the advantage of using H2O instead of H2S?
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53 views

What is the purpose of THC for a Cannabis plant?

Why does a Cannabis plant produce THC? This question is brought up drawing an analogy to nicotine in tobacco, where nicotine is developed by tobacco plants as a pesticide. Is THC a pesticide as well? ...
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40 views

How does trees know to balance themselves so that they never fall down [duplicate]

Well i was flying kites today I saw a tree and its branches were spread around in random directions... I would like to know that how do these trees know to nourish their branches in some direction so ...
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504 views

Why are there so many medicinal plants?

Here is wikipedia page containing a list of plants used in herbal medicine. One might first want to argue that many of them actually do not have any medicinal/beneficial effect on heatlth. I think we ...
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1k views

The mystery of coconut tree

Could anyone please explain to me, why the nail which is nailed in a coconut tree is not raised from ground level, when the tree is growing up?
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108 views

What is this plant?

It was found in Eastern Pennsylvania (in the United States) in a deeply wooded area.
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118 views

What virus transforms full grown plants?

I read an article by a gardener describing how a virus had transmitted a negative trait to his plants. It rather shocked me, because I hadn't realized that a virus could transform an adult plant. I ...
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557 views

Family tree for edible plants?

I am looking for a family tree for plants, particularly veg / herbs / fruit. Something similar to: If it could be slightly less technical than all the Latin ...
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1answer
64 views

What are the mechanistics of stinging nettles?

There is a lot of research on why nettle extracts causes skin irritation and a stinging sensation. However, I cannot find information on how the extract is injected in human skin. Similarly, I haven't ...
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1answer
620 views

What is the name of this flower with purple leaves and orange inner part in NYC?

I've photographed this flower a few days ago in New York City: Does anybody know the name of it? (and how is the orange part called?)
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2answers
96 views

What chemical or biochemical agents do plants use to inhibit each other's growth?

As I just learned, allelopathy is the action by which plants regulate the growth of other nearby plants. I have hear of ethylene is a general signal for growth and fruit ripening in particular, but ...
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52 views

Plant identification

What plant species is this? Its stalk looks like a grapevine, but the leaves & flowers not. It bloomed this week (Mid-June). I have found it in Turkey, Amasya. If you want, I can add more ...
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120 views

How common is bacterial mediated transformation? In plants? In animal cells?

The most common method to transform plants is by soaking plant tissue in cultures of agrobacteria (this is not their current classification) which transfer DNA into the plants. Is lateral gene ...
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613 views

Why do plants' leaves become enlarged in low light areas?

Why do almost all plants in shade have a smaller stem structure and larger leaf than that same species grown in a well lit, sunny area?
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40 views

What is this species of tree?

In my city, there is a unique tree, with thorns all over it. I would like to know - what species is this?
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275 views

What does the empty space in the bamboo stem do?

Is the empty space inside a bamboo stem a xylem? And why is the space so large?
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511 views

What does “chlorophyll photosynthesis peak” mean in relation to photon wavelength?

When reading about how green / leafy plants work, I saw that they have chlorophyll A & B, which allow the plant to use the energy from light by capturing and transforming. When reading about ...
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3answers
282 views

Where does crop biomass come from?

Each year, large volumes of crop are harvested from fields. Where does this biomass get replenished from?
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146 views

Convergent evolution of fruits

Many fruits are not homologous, originating from different parts of a plant. Yet they all have similar properties: Ripe fruits all have yellow to dark red color They all have a lot of water and ...
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65 views

What plant is it?

Do you know what plant is it? I found it in France
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72 views

Do you know what plant it is?

I saw this plant when I was on my trip to the Ukraine. I wonder if those berries are edible. Thanks a lot in advance.
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69 views

Which plant is this?

I'm curious what plant this is! I found it at 37°52'23.2"N 122°16'55.3"W (north of Oakland, California, USA).
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306 views

What does x in “Miscanthus × giganteus” name stand for?

I came across a species name that contains "x" in its name, namely Miscanthus × giganteus. What does this symbol stand for and is it commonly used in taxonomic nomenclature?
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229 views

What does the root “phyllum” mean used botanical binomial nomenclature

I often encounter the root "phyllum" in bionomial names in botany, but I've had trouble finding an actual definition for this root in any Latin dictionary outside of its taxonomic meaning. From ...
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268 views

is it necessary that every theca of an angiospermic anther must contain two microsporangia

i basically don't know the procedure or sequence of steps involved in the formation of anthers but i have read it somewhere it is formed from the dedifferentiation of shoot apical meristem of the ...
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1answer
360 views

Are there any air-plants with parts that are edible for humans?

Are any air plants (Tillansia sp.) safe for humans to eat? I haven't been able to find whether or not there are. Pineapple is in the same family (Bromeliaceae), but isn't an air plant.
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1answer
74 views

What is the cause of the spots on this leaf?

On a hiking trip to the Alps I found trees whose leaves showed those spots you see on the picture. I am curious about what the cause is. Higher resolution pictures of front and back side.
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383 views

Plant a whole fruit or only seeds?

I'm trying to figure out whether it is better for the plant to reproduce by planting its whole fruits with seeds inside them, or picking the seeds out and planting them without the fruit. In my case ...
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1answer
31 views

What are the hairs/spikes on the edges of these leaves for?

Windows 7 has a wallpaper/background which shows an attractive, leafy plant with fine hairs or spikes on the edges. What might these be for, and what sort of plant is it? My initial (uneducated) ...
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1answer
178 views

What are these white spots on a dracena

I have a Dracaena Marginata which started to have some white spots. They turn out to be some kind of "mold" which can be removed when swapping the leaf and then leaves some discolored spots ...
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2answers
64 views

Can anyone ID this flower plant by the photo?

Can someone identify this plant? It has big red flowers when it flowers! Not sure if it is native, but it is in my grandmothers garden in Vancouver, British Columbia, Canada.
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1answer
899 views

Why are there more stomatal openings on the lower surface of a dicot leaf?

This causes more transpiration to occur from lower leaf surface. What's the exact reason for why are there more stomatal openings on the lower surface of a dicot leaf?
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1answer
179 views

How much pollen is needed to pollinate a flower?

Assuming 100% of the pollen gets delivered to exactly the locations it needs to pollinate a female flower, how much pollen is needed to pollinate a flower? If it's more than one unit of pollen, what, ...
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1answer
62 views

Why are the genomes of some trees so large?

For example, the current longest known genome belongs to a tree: http://motherboard.vice.com/read/the-largest-genome-ever-sequenced-belongs-to-a-tree I have heard that this could potentially be ...
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1answer
94 views

How can a plant resist glyphosate (Roundup) herbicide?

In my area, the most common weeds that strongly resists (N-(phosphonomethyl)glycine) (glyphosate) are the horseweed, or mare's tail, Conyza canadensis, and Canada thistle, Cirsium arvense There are ...
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2answers
579 views

Where do trees get their shape?

Does anyone know any good resources dealing with shapes of trees? For example, pine trees are cone shaped for optimal absorption of sunlight, but lone pine trees growing in isolation (and other ...