Are infrastipular prickles really modified stipules

While looking into shoot tip abortion, I came across a fascinating book, ‘On Buds and Stipules’ by Sir John Lubbock.

On page 188 the author discussed Rosa persica:
“The stem is prickly, and the frequent occurrence of the prickles, sometimes in pairs, at the base of the leaf has led to their description as stipules; for instance, by Boissier in his great ‘Flora Orientalis’.”

Lubbock did not offer his opinion on the accuracy of this observation. But it did get me to thinking about infrastipular prickles in general. Lubbock gave examples of prickles that are undoubtedly stipules, such as those of Robinia pseudoacacia.

Now, compare those to the infrastipular stipules of Rosa woodsii.

The relationship of stipules to leaflets is sometimes revealed in hybrids. For example, the orange has simple leaves. The trifoliate orange (Poncirus trifoliata) appears to have three leaflets, but technically the side-leaflets are stipules. But a hybrid of trifoliata and the Thompson Navel orange shows many 5 foliate leaves.

I am interested in the occurrence of infrastipular prickles in rose hybrids, and whether these are correlated (linked) with other traits of the parent that provided them.

It is an interesting question and your suggested approach using hybridity seems like a really good one but wonder if ploidy differentials might interfere. My thought experiment would use moyesii, which has huge and long stipules attached along the leaf stem but, being heavily polyploid, might it not yield both stipules and prickles?

Actually, I wonder if I have already done the experiment. I will need to have a look in the spring.

Infrastipular stipules seem to be a long-established character of Rosa, whether habitual or occasional. Getting these to revert to a more “traditional” sort of stipule might require intergeneric hybridization - like the hybrid of Poncirus and Citrus seemingly reverting to an ancestral form with pinnate leaves.

And on that possibility, I recently found a very suggestive paper by O. F. Cook, ‘Jointed leaves of Amygdalaceae.’ (1912).

Amygdalaceae is the old name for Prunus. Cook pointed out that the joint at the base of the leaf, and nectaries on the leaves of some apricots, are evidence that these species are descended from ancestors with compound leaves.

The Gardeners’ Monthly and Horticulturist, 29: 376-377 (Dec 1887)
On The Stipules Of Magnolia Frazeri.
Thomas Meehan
“In many species of roses, especially in Rosa Kamtschatica and Rosa cinnamomea, the stipules could be noted increasing, and the size of the leaf blade diminishing on the branch as it approached infloresence. Often the tips of the sepals would develop to minute leaf blades; and in a few instances he had seen the same appendages on abnormal petals. Often the stipules, especially in Rosa Kamtschatica, would have the red colors of the petals, when at the nodes, immediately below the axis from which the peduncle proceeded. There could be no possible doubt in the minds of those who would carefully compare, and watch for occasional aberrations, that the petals of the rose were rather transformed petals [sic: I think this should be “transformed stipules”] than complete leaves.”

the petals of the rose were rather transformed…transformed stipules…than complete leaves.

Hmmm. I would think that this question has already been answered by the folks who study inflorescence. Does anybody here from academia know if petals and stipules are the same bird?

I would be interested to learn of any research subsequent to Meehan’s.

BTW, the Bot. Reg. illustration of Rosa ferox shows the red pigment in the stipules immediately below the flower. At this point in my research, R. ferox and R. kamchatica seem to be selections of the same, small-leafed species.


A further report from Meehan on stipules and petals:

Proceedings of the Academy of Natural Sciences of Philadelphia 41: 53-66 (1889)
Contributions to the Life Histories of Plants. No. IV
Thomas Meehan
Clear as it is to the mind that when carefully traced, the petal of a rose is formed of an enlarged stipule, and not of a fully planned leaf, the positive evidence is not furnished as freely as in the case of the sepal, but specimens of > Rosa humilis> , sent to me in 1883 by Miss Jennie E. Whiteside, of Harmonsburg, Pennsylvania, give an excellent illustration. This form has been figured and described by Mr. Sereno Watson in the > Garden and Forest > for February 13th, 1889 as > Rosa humilis> , var > triloba> . The trilobed petal is simply a case in which the usual stipule forming the petal of the rose, has again had its normal growth accelerated towards a perfect leaf. The central lobe is in fact no more than a dilated petiole, with the stipule represented by the two lateral lobes, in its normal position at its base. The same process from the total arrestation of petiole and leaf blade to the abnormal dilation of the stipule to form the petal, can be traced in magnolia, as made plain in the paper above cited.
Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia - Google Books

Rosa humilis var triloba

I’ve been reading about extrafloral nectaries and how they attract ants that devour sucking insects that bother the same plants. In Guatemala, the Kekchi cotton plays host to keleps (a species of ant) that sip the nectar and dine on boll weavels.

A little more searching turned up this item;

Annual Report of the Board of Regents of the Smithsonian Institution for the Year ending June 30, 1896 pp. 421-422
The biologic relations between plants and ants
Dr. Heim
Associate of the Faculty of Medicine at Paris

Along the edges of the leaves of the > Rosa Banksiae > are found perifoliary nectaries that attract great numbers of a large black ant (> Camponotus pubescens> ). The presence of these ants preserves the rose from the attacks of a hymenopterous insect (> Hylotoma rosae> ). We owe an interesting experiment upon this subject to Beccari. On a branch of > Rosa Banksiae > attacked by ants he placed a branch of another rose bush attacked by the larvae of > Hylotoma. > Incommoded by the ants, these larvae took refuge upon the youngest buds, unprovided as yet with nectaries, and consequently not visited by ants. It is to be remarked that the Banks rosebushes, which are rarely or never attacked by Hylotomas, are destitute of prickles. We may probably admit that there is a correlation between the presence on plants of thorns or prickles and that of leaf-eating insects. Is it not due to the protection given by ants and other sting-bearing hymenoptera that the Banks rosebushes attain the great age that some of them are known to do? We may cite as an instance one of these bushes planted in 1803 by Bopland in the garden of the marine hospital at Toulon, which has a stem a meter in diameter at the base and bears each year from fifty to sixty thousand flowers.

The leaves of peach, apricot, and cherry trees may, as there is reason to suppose, be derived from compound leaves. The nectaries which they carry on the petioles should then have the significance of aborted leaflets filled with sweet stores.

Annual Report of the Board of Regents of the Smithsonian Institution Showing ... - Smithsonian Institution. Board of Regents - Google Books

So, here is another reason to breed with Rosa banksiae, while paying attention to which seedlings are most often visited by ants.

And another:

The Biology of Nectaries, p. 193 (1983)

Extrafloral Nectaries: Their Structure and Distribution
Thomas S. Elias
One or more, often paired nectaries of the Flach or Hoch type are present at the distal part of the petiole in many species of > Prunus > and some species of > Rosa> . In addition, some members of this genus have branched stipules which are nectariferous.
The Biology of Nectaries - Barbara Bentley, Thomas Elias, Thomas S. Elias - Google Books

Has anyone seen ladybugs (or ladybird beetles) sipping nectar from the leaves or stipules of roses?

Interesting, thanks, Karl. I have not noticed that.

The statement about a Rosa banksiae with a trunk a meter in diameter seems to be a mistranslation. I found the German text, which states that the trunk was a meter in circumference.

The original source was Beccari’s ‘Piante ospitatrici ossia piante formicarie della Malesia et della Papuasia,’ (1885) So, the association of Rosa banksiae with the black ants apparently was observed in the rose’s natural habitat.

However, both the ant and the rose sawfly seem (from what I’ve been able to find) to be natives of Europe.

Delpino (1899) continued the study of extra-floral nectaries. He stated that Beccari had made his observations in Florence, then added his own from Bologna.

Delpino confirmed Beccari’s observations of leaf-nectaries on Rosa banksiae, then added that these are also found on the leaves of R. bracteata, though they are less numerous. Furthermore, in Bracteata the nectaries are active only on the young leaves.

Bullettino dell’Orto botanico della R. Università di Napoli, Volume 1 (1899)
Piante Formicarie (Seguito)
Prof. Federico Delpino
Rosa bracteata. – L’inspezione attenta del diportarsi delle formiche mi ha rivelato la esistenza dei minuscoli nettarii di questa specie. Invero i suoi vigorosi rampolli scarseggiano di spine, e mancano dei soliti peli glandolosi allontanatori delle formiche. Le foglioline sono serrate, e l’apice dei denti, a vece di essere occupato, come nelle altre specie di rose, da collofori, porta un piccolo nettario mellifluo. Questa secrezione, ch’è poco diuturna, riscontrandosi soltanto nelle foglie giovani, adesca un certo numero di formiche, che dimorano verso le sommità vegetative dei rampolli medesimi, e passano lentamente dalle foglioline d‘ una foglia a quelle di un’altra, visitando metodicamente l‘apice dei denti fogliari. La quantità del miele emanato è di gran lunga inferiore a quella della Rosa Banksiae; ma è anche proporzionalmente minore il numero e la statura delle formiche accorrenti. Prendendo la media di molte osservazioni ho rilevato nella sommità di ogni rampollo la presenza o di una sola formica di una mezzana statura, o di quattro o cinque di piccola.

È notevole cosi in questa che nella Rosa Banksiae la mancanza dei soliti peli glandulari; i quali veramente qui sarebbero un contro senso, perocchè sono allontanatori delle formiche.

Bullettino dell'Orto botanico della R. Università di Napoli - Università di Napoli. Orto botanico - Google Books

In reading the early descriptions of Rosa rugosa and its varieties, I began to wonder whether the needle-like prickles (glandular acicles) were derived from trichomes. A quick search turned up this:

Understanding Plant Anatomy, p. 123 (2009)
By S. R. Mishra
"Prickles are classified as trichomes, no matter how massive they may be, whenever it is clear that they arise from the epidermis and are not modifications of any other organ.

As a matter of fact, the large prickles of Rosa and the vascular prickles on the fruit of Horse Chestnut are connected with simple hairs by all gradations of finer prickles."
Understanding Plant Anatomy - S.r. Mishra - Google Books

Trichomes are a fascinating subject on their own. Beal (1878) described and illustrated some of the diversity of structure and function he found among trichomes of various plants.

And Cannon (1909) compared the trichomes of some hybrids with those of their parents.

Pondering this information, I remembered a very curious curiosity I read about years ago, Begonia phyllomaniaca. Could there be a connection between the proliferation of small leaves on stems and leaves of this begonia? Yes, according to Smith (1919).

“My observations contradict those of Prillieux and confirm those of Verlot and of Caruel that buds may arise from the ordinary trichomes. They may develop either from the base or the middle of acicular hairs. Such hairs arise from a red tissue, the other parts of the epidermis being green. I have also seen them developing from the base of glandular hairs which are abundant on the young internodes, but they are not restricted to these pairs.”
Smith: Begonia phyllomaniaca (1919)

Another item I found several years ago is also of some interest. MacDougal (1903) noted that the orchid Cypripedium montanum normally produces two types of trichomes, the pointed and the knobbed.

… the growth of Cypripedium in darkness is characterized by a non-development of the pointed hairs on the leaves, and the excessive development of the glandular trichomes.
MacDougal: Cypripedium montanum in darkness (1903)
The influence of light and darkness upon growth and development - Biodiversity Heritage Library

So, the various types of trichomes (and their derivatives) are largely independent in their heredity and in their environmentally modified expressions.

Which brings me to the Rose matter.

Les Roses, pp. 47-48 (1817)
It is from one of our drawings that this Rose [R. kamchatica] has been engraved for the garden of CELS, page and figure 67. By comparing this individual with that which accompanies our description, it will be easily seen that in less than eighteen years, this rose has undergone considerable modifications in the length or density of the spines, and in the shape of the leaflets.
Untitled Document

In fact, this Rosa kamchatica had become as “fierce” as R. ferox Lawrance. The above link shows Redouté’s two illustrations, along with the one from the Botanical Register.

My suspicion is that the original population of R. kamchatica is polymorphic for a gene (or two) that allow for an extreme development of the glandular acicles, but the trait is suppressed by some environmental condition active in Kamchatka. When various specimens are moved further south, some of them become “fierce” while others don’t. This suspicion is not contradicted by Palibin (1899) who noted that Rosa rugosa var. ferox is widely distributed, but is NOT found in Kamtschatka.

Another example of morphological traits being expressed differently under different environmental conditions was noted by Hurst.

Experiments in Genetics (1925)
Charles Chamberlain Hurst
Chromosomes and characters in Rosa and their significance in the origin of species
In the most complex case studied, in the octoploid species BBCCDDEE (> R. acicularis > Lindl.), the four double septets seem to work more or less in relays in different parts of the plant at different times and seasons, resulting in a periodic predominance of one septet over another in certain parts of the plant, the general result being more or less a mosaic of the four septets of characters arranged end to end or side by side.
Hurst: Chromosomes and Characters in Rosa (1925)
Naturally with four double septets working equally and independently in an octoploid species, only about one-fourth of the characters of each septet can be represented at one time.

One final note on the function of glandular organs:

ACTA AGROBOTANICA, Vol. 67 (4), 2014: 13–24
© The Author(s) 2014 Published by Polish Botanical Society
Aneta Sulborska, Elżbieta Weryszko-Chmielewska

A b s t r a c t
Due to the presence of secondary metabolites exhibiting pharmacological activity, the flowers of > Rosa rugosa > Thunb. have found application in traditional and folk medicine. The essential oil obtained from them is also considered to be a phytoncide. The morphological and anatomical characters of glandular trichomes located on the sepals of > R. rugosa > were studied by light and scanning electron microscopy. Using histochemical tests, the type of secretion produced in the trichomes was determined and its contents were compared with the secretion produced by the papillae on the petals.


I have come across three items that may be of interest.

David Don (1830) agreed that the prickles beneath the leaf are modified stipules.

Alexander von Bunge (1830) broke new ground by explaining that this species has no leaves. What passes for a leaf is actually a pair of stipules that have fused. Bunge: Rosa berberifolia (1831)

I find Bunge’s observation to be particularly interesting because Meehan (1887) offered a similar explanation for the petals of roses and other other flowers.

This model is suggested by Rosa rugosa with a colored bract.

And Rosa humilis var. triloba, is further evidence with petal halves fused to a partial, modified petiole, as if the leaf form is trying to re-emerge.

Another oddity along these lines is ‘Marquise Boccella’ with sepals reverting to leaves.

George F. Wilson (1885) discussed the various yellow roses known at the time. His relevance here is a particularly detailed drawing of Rosa x hardii.

Note the terminal leaflet on the leaf near the center of the page. It looks like it is tempted to split. Maybe our distinction between stipules and “proper” leaves is not as clear as we might imagine.

Now look at the bottom leaf. The leaflets appear to be alternate rather than opposite. This reminded me of the arrangement of spikelets on maize tassels.

Figure A shows spikelets mostly alternating left, right, left, right, except in the circled area where they are practically opposite. This sort of tassel is associated with Northern Flint with 8 rows per ear. Figure B has the spikelets mostly opposite, except in the area circled. This would be appropriate for a Southern Gourdseed with ears of 30 or 32 rows.

Oddities that give some clues about evolution are sometimes found in hybrids. With maize, such “Mutants” may be produced by plants grown out of their proper season. And maybe the hot Tennessee summer had a strange effect on the Peruvian Purple, which did so nicely in California.

This one is what happened when I raised a Southern Gourdseed in autumn. No radio-isotopes or toxic chemicals required.

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@Karl_K thank you for sharing these references and illustrations! It is fascinating to learn more about these anomalies and what they might mean.
Your pic with the terminal leaf attempting to split reminded me of an unusual one I saw on my “Boufarik” (which may be an OP seedling of Rose de Rescht? Sold by Ducher).
Leaf with three distinct midribs:

Thanks for the excellent picture. I hope to find more such documentation for the underlying mechanisms of leaf formation.

It seems that the apparent pairs of leaves are really alternate, but a rhythmic suppression of stem elongation makes them appear opposite. That is, a leaf to the left is followed by a short bit of stem (internode). The right leaf is then followed by a long internode. So: left, short, right, long, left, short, … and finally the terminal leaflet.

I reread Harkness’s 1977 paper on his experiences with Hulthemia.

“All the Canary Bird crosses survived, …”

“The leaves were extremely interesting. There were variations of size and density between the hybrids, but they all had compound leaves of 7 or 9 leaflets, or occasionally 5 to 11. The terminal leaf was in most cases strange, being irregular, as though partly cleft into two or three. Sometimes the main vein can be seen to branch towards the imperfectly cleft parts of the terminal leaf. Rudimentary leaves are common where lateral growths arise.”

Alas, no clear pictures of those interesting leaves.

He also wrote, “Two seedlings of H. persica x R. rugosa alba also failed. Probably no two diploid species of roses are more dissimilar than H. persica and R. rugosa; at all events the seedlings from that cross try to make leaves from the seedling stem at intervals of 3 or 4 mms, and their effort exhausts them before they are very high.”

I wonder whether the suppression of elongation that normally works only on the developing leaves, somehow interfered with the production of leaves on the cane. Just guessing.

I had a rose (some 30 years ago) that did an odd trick. I thought it was ‘Robin Hood’, but I don’t have pictures. As well as I can remember, two pairs of leaflets seemed to be separated by a short internode, giving them the appearance of an X. That would be … left, short, right, short, left, short, right, long, … Just a hiccup in the normal rhythm.

Now that I’m thinking of the leaf as a growth pattern, I wonder how much information I’ve been ignoring that might help distinguish species and some cultivars.


Thank you so much! You have spared no efforts to compile and share with us these amazing insights and valuable informations. In the future I will meet the roses with an even more vigilant and sensitive eye.


@Karl_K I have read that article by Harkness many times, it is extremely interesting to me to learn from his experiments that led to Nigel Hawthorne as I am trying to go down the path of rugosa×hulthemia myself, albeit in a lesser, diluted, more roundabout way.
You said: “It seems that the apparent pairs of leaves are really alternate, but a rhythmic suppression of stem elongation makes them appear opposite”.
I went and had a look in the garden after reading your comment and sure enough:
Young leaf of Emilia Castelli:

Wonky leaf of Chios rose:

Edited to add: A leaf of Wild Edric, whose stipules seem to be trying to look like leaflets:


Thanks for the kind words. When I was a kid, I learned to make use of bibliographies. It didn’t occur to me at the time that someday I’d be making bibliographies and connecting dots. This is a lot more satisfying to me than just reciting isolated facts.


Once upon a time, long ago and far away, I was reading one of Euell Gibbon’s books on foraging. He mentioned the uses of cattails, so I got curious. I drove out to a nearby lake and found a fine stand of very tall cattails. I looked, but could not see any indication of the swelling he described as the clue to the immature “tails”. I grabbed hold of one and bent it over to feel the stalk, and pull off the young leaves. Bingo! I had one. And when I stepped back to have another look, I saw them all over. It was like someone had marked each slight swelling with a highlighter. The “information” was right in front of me all along, but I had not been “attuned” to it until I felt one.
I had to look up ‘Wild Edric’. Another Rugosa, I see. You already have me re-visiting the confusing Rugosa clan, so I’ll save further comments until I can get my notes together. For one thing, there have been more than a few hybrids that have been passed off as
Rosa rugosa. These mostly involve Rosa davurica, the Far Eastern version of R. cinnamomea/majalis. That could account for the extra-large stipules.

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Karl k, thank you for sharing that story. It’s amazing how new information can change our gaze on the world, making us notice what was right in front of us the whole time. It has been a complete game changer for me to find this forum and be able to scour the archive for all kinds of fascinating information. I am really grateful that you are sharing your research here!