Inflorescence Anatomy: bract vs. calyx

[spurr]

Hello,


It seems there is a good bit of confusion (or at least disagreement) about usage of “bract” vs ”calyx” (re a collection of “sepals”), with respect to the flowering tissue (inflorescence) of female cannabis plants vs. non-flowering stage of growth [1,2,3]. It's not uncommon for growers [4], and even highly respected cannabis researchers (such as P.G., Mahlburg and T., Hemphill, et al. [5]), to use the term “bract” when referring to a collection of (flowering tissue) “sepals”, enclosing the ovule [6,7]. However, many other academic resources [8,9,10,11,12], incl. academics in the cannabis world (ex., R.C.Clarke [13]), refer to the collection of (inflorescence) sepals as calyx.



I use of the term "calyx" when referring to a collection of sepals. Below I edited the pics (text and lines in red), I edited to what I believe is correct, AFAIU. What do others here use, "bract" or "calyx", and why?





(all the red lines and text are my edits)


[1]

​

[2]

​

[3] (leaf "stipules", sometimes called bracts)

[4] “Marijuana female flower: calyx or bract?”
By George Grass (2003)
http://www.marioptics.webs.com/calyx.html




[5]

• Turner, J., J. Hemphill, and P. G. Mahlberg. 1981. Interrelationships of glandular trichomes and cannabinoid content. I: Developing pistillate bracts of Cannabis sativa L. (Cannabaceae). Bull. on Narc. 33:59-69.
• Hemphill, J., J. Turner, and P. G. Mahlberg. 1980. Cannabinoid content of individual plant organs from different geographical strains of Cannabis sativa L. (Cannabaceae). Jour. Nat. Prod. 43:112-122.
• Turner, J., J. Hemphill, and P. G. Mahlberg. 1980. Trichomes and cannabinoid content in developing leaves and bracts of Cannabis sativa L. (Cannabaceae). Amer. J. Bot. 67:1397 1406.

[6]

[7]

[8] http://www.botany.hawaii.edu/faculty/carr/api.htm

​

[9] http://waynesword.palomar.edu/terminf2.htm




[10] http://extension.oregonstate.edu/mg/botany/flowers.html




[11] http://extension.oregonstate.edu/mg/botany/leaves2.html




[12] http://www.cals.ncsu.edu/plantbiology/ncsc/Spring_flora/glossary.htm




[13] "Marijuana Botany: Propagation and Breeding of Distinctive Cannabis"
By Robert Connell Clarke
Ronin Publishing, 1993
ISBN 091417178X, 9780914171782
p. 161

At this point the terminolog of bract and calyx should be clarified. A review of the literature shows that much confusion exists around the nomenclature of the bracts on a cannabis plant. The term bract most commonly refers to the membranous sheath surrounding the ovule which is herein referred to as the pistillate calyx or calyx. Bract is sometimes used to describe the stipule (leaf spur) which appears on both sides of the axis of the petiole (leaf stalk) with the stem. The term has also been used to describe the small reduced leaf that subtends each pair of calyxes. It is my contention that the word calyx should be used to describes the five part carpel structure of the staminate flower, or the five part fused tubular sheath that surrounds the ovule and pistils.

The word bract is preferably acceptable for the small reduced leaf subtending a pair of pistillate calyxes, and stipule is the correct term for the leaf spur. Calyx implies that the flower part is reproductive in nature, and bract has a distinctly vegetative connotation. It is unfortunate that bract has been so misused as it is really an excellent descriptive word for a small reduced leaf.To quote from Roget’s Thesaurus: “Bract, bractlet – foliage, foliation, leafage, stalk, leafstalk, petiole,… stipule,… leaf,… leaflet, blade,.. lamina,… seedleaf …calyx leaf.
Calyx – sac ….pocket…. vescule…pericarp ….capsule…pod…”

It seems obvious that bract describes leaf structure and calyx describes floural structure.

​

 

[spurr]

Oh yea, what many cannabis growers call a "pistil" is really the 'stigma-style'. A "pisitil" is a term for the the stigma(s), style(s) and ovule. See the pics above for examples.

 

[Microbeman]

You bring up a topic which is in one of my very first posts here on ICmag. It went pretty much unnoticed.

I once (1998?) was engaged in a huge argument with the ---- dispensery over this because at the time I thought it foolish that they were instructing me to trim off bract leaflets which were laden with the highest density of glandular trichomes. I showed them photos and scientific literature to back my case. At that time they said the calyx capsule was the bract; not in my botany. They and many are in the habit of trimming off the outer (pointy) portion of the floral bracts with scissors (along with other leaves) leaving behing the stubby portion of the bract, attached to the stem which affixes it to the cola stem. I tried pointing out how stupid this is to remove the best part of the bract and leave the shit behind to be smoked and that no indigenous peoples practiced this, to no avail. If they were going to accept our produce, it had to be trimmed this way so it looked pretty. To work around this we dried out the flowers totally to a point where deft fingers could fairly rapidly snap 95% of the bracts off at the stem. We then had more material for extract and they had what the think they wanted.

 

[MrFista]

The last photo - I dunno! But - Bract? - A modified or specialised leaf. I can see how all the confusion began...

The floral tubes are composed of petals fused together. The part you label bract is a sepal imo. But could easily be argued to be a bract as the definition is so broad. The stigma you point to is imo an anther but that flower is no easy study. Note the floral tubes are not overall - some flowers on that inflorescence lack the fused petals altogether.

I'll have a look through what the prof had to say on the subject see if it sheds any more light. I totally agree bract is vegetative (leafy) and calyx is a flower part. Take an acorn, the cupule (cup holding acorn) is a cluster of bracts. The seed (nut, flowering part) itself is a separate thing.

 

[Microbeman]

Here is some info which may help. A couple of pretty decent sites IMO

http://www.biologie.uni-hamburg.de/b-online/e02/02e.htm
“Inflorescences are arrangements of more than one flower, like bostryx, head, cyme etc. They are modified parts of the shoot with leaves typically reduced to leaflike bracts.”


http://waynesword.palomar.edu/terminf1.htm

 

[spurr]

You bring up a topic which is in one of my very first posts here on ICmag. It went pretty much unnoticed.

I once (1998?) was engaged in a huge argument with the ---- dispensery over this because at the time I thought it foolish that they were instructing me to trim off bract leaflets which were laden with the highest density of glandular trichomes. I showed them photos and scientific literature to back my case. At that time they said the calyx capsule was the bract; not in my botany. They and many are in the habit of trimming off the outer (pointy) portion of the floral bracts with scissors (along with other leaves) leaving behing the stubby portion of the bract, attached to the stem which affixes it to the cola stem. I tried pointing out how stupid this is to remove the best part of the bract and leave the shit behind to be smoked and that no indigenous peoples practiced this, to no avail. If they were going to accept our produce, it had to be trimmed this way so it looked pretty. To work around this we dried out the flowers totally to a point where deft fingers could fairly rapidly snap 95% of the bracts off at the stem. We then had more material for extract and they had what the think they wanted.

Interesting. I do the same thing, due to what people want: "bag appeal".

 

[spurr]

The last photo - I dunno! But - Bract? - A modified or specialised leaf. I can see how all the confusion began...

The floral tubes are composed of petals fused together. The part you label bract is a sepal imo. But could easily be argued to be a bract as the definition is so broad.

You could be correct, I can see it both ways. I took that image from the University of Hawaii botany department (http://www.botany.hawaii.edu/), web site of a professor*. According to the link above the pic:

"Astrantium major. This species has showy bracts at the base of the umbel. It also has larger sepals than typical for the family. Note the small, pinkish inflexed petals and the inferior ovaries."
​

I used that picture because it showed many different parts of inflorescence. As I'm sure you're aware, but for others reading (I'm sure MM is aware too), the "umbel" is part of "an inflorescence in which a number of flower http://dictionary.reference.com/browse/flowerstalks or pedicels, nearly equal in length, spread from a common center." (dictionary cite), ex., Nerine bowdenii:

Umbel:

* http://www.botany.hawaii.edu/faculty/carr/

The stigma you point to is imo an anther but that flower is no easy study. Note the floral tubes are not overall - some flowers on that inflorescence lack the fused petals altogether.

You could be correct. It could be an anther, I am not too familiar with that flower. I'm unclear about the difference between fused petals and non-fused petals with respect to that picture. I don't know enough about that plant and its' flowers to know if that's normal due to age, stage, etc.

I'll have a look through what the prof had to say on the subject see if it sheds any more light. I totally agree bract is vegetative (leafy) and calyx is a flower part. Take an acorn, the cupule (cup holding acorn) is a cluster of bracts. The seed (nut, flowering part) itself is a separate thing.

Great, let us know what your professor has to say

 

[spurr]

Here is some info which may help. A couple of pretty decent sites IMO

http://www.biologie.uni-hamburg.de/b-online/e02/02e.htm
“Inflorescences are arrangements of more than one flower, like bostryx, head, cyme etc. They are modified parts of the shoot with leaves typically reduced to leaflike bracts.”

Thanks for that, I'm off to check it out now.

http://waynesword.palomar.edu/terminf1.htm

That's a good picture, I agree. In fact, I almost used that instead of the last picture I posted (the one Mr. Fista is writing about). I used the other picture (the last in my first post) because it was of a real flower and I thought the colors would help people understand.

I'm glad you posted that image because it has more info, and that site is good too. I linked to another page from that site in my first post. It's kind of funny, because when I read "waynesworld" in the URL, I thought "oh, great, this is gonna be a joke" ... and it was far from a joke.

To my understanding those flowers form the umbel, in that image.

 

[Microbeman]

I think a lot of the misunderstanding in the cannabis world comes from the misinterpration of (well actually a plethora) of what the flower construct is, due to the use of the word 'bud'. What most refer to as a bud is actually a floral structure or inflorescence comprised of multiple flowers. Dependent upon the genetics of the particular plant and in some respects environmental conditions it presents with a varying density and size of bracts interspersed in the inflorescence. It is my observation that the outer to mid-section of bracts are usually coated in just as high or even higher density of grandular trichomes than the outer coating of the calyx. This outer sheath of the calyx, as you have noted, is even refered to (mistakenly I think) by monitoring officials in the commercial hemp industry (in Canada), as the bracts

 

[habeeb]

all I've seen about this was a article from mel frank ( yes.. I know mel frank ) very recent article like 1 year old I believe

here it is: if you want a higher res, well IC limits the size of pics, so let me know if you need higher res



to me. I don't care. I keep it simple by saying that's a female plant, and that's a male plant. think if you talked to a baby how you would tell it... I find the more scientific I get with plants, the more un-enjoyable my hobby gets, but that's just me

 

[spurr]

@ habeeb,

Thanks for those images, I'll check um' out ... good ol' Mel Frank

I think people can be divided into (at least) three categories with respect to science and growing: one group feels like you, another group feels the complete opposite (the group I fall under), and a third group falls between group one and two. I think all groups have valid points, and I'm glad we all get along and offer useful info here at icmag, I think each group benefits the both other two.

 

[spurr]

all I've seen about this was a article from mel frank ( yes.. I know mel frank ) very recent article like 1 year old I believe

here it is: if you want a higher res, well IC limits the size of pics, so let me know if you need higher res

Good ol' Mel, still wrong after all these years.

Images on page one and two, Mel use of bract instead of calyx (or sepals, it's unclear because he used the term "bracts"); then scanning pages I see he uses bract(s) instead of calyx, often (doh!).

And does it seem a bit asinine to call Cannabis spp. inflorescence "marijuana", in an article entitled "Cannabis Nomenclature" ... or is it just me?!

 

[spurr]

I wanted to add a pic of flowering cannabis, after what MM wrote, so people can see what (I think) he is referring to, in terms of flowering bract:

@ MM: Please correct me if I'm wrong.

@ Mr.F: How does the below jive with your understanding?

 

[habeeb]

@ habeeb,

Thanks for those images, I'll check um' out ... good ol' Mel Frank

I think people can be divided into (at least) three categories with respect to science and growing: one group feels like you, another group feels the complete opposite (the group I fall under), and a third group falls between group one and two. I think all groups have valid points, and I'm glad we all get along and offer useful info here at icmag, I think each group benefits the both other two.

very true..

I feel I am not ever gonna be a breeder, be a scientist, or anything where I need to know specifics..

good points spurr. there are many a mix here all bouncing things off each other

 

[Microbeman]

Ya the photo seems accurately delineated except I use the phrase 'floral bract' rather than 'flowering bract' simply because the bract is not flowering.

 

[MrFista]

I like that photo spurr it seems the best example so far considering we are examining cannabis and imo is accurate. Nice you labelled the leaf too to show one is a leaf, and the bract as a modified leaf.

 

[Avinash.miles]

this article is great bcuz it verified what i already believed, however, im happy to learn the correct term for sepals (not calyx lips)

 

[Jamaica Nice]

Good thread spurr, thanks for the info, same for yo microbeman, i did`t see your post could you give me the link?
found it very helpful
i wonder if i could translate and post some images on my site, quoting the source, for people who is just starting here in Argentine.
thanks again, and sorry for my aboriginal english jajaja

 

[LittleAmsterdam]

Thank you for the anatomy lesson. Cool stuff ! I'm always fascinated by these things, specifically 'Seeds'

 

[Sheriff Bart]

pics 1 and 2 your 'bract' is actually a stipule

#3 that is a palmately compound leaf with leaflets not stipules