Transitions Studies in Flowering Plants

by Rolf Baumberger


Is Antirrhinum striatum/pseudomajus, a similar system?

The author is interested if also in this genus one can see a transitional process going on just now? The first results will be published here in 2020-21!

Fig. 1: Distribution of A. majus species and in between morphs in a Girona valley.

Fig. 2: 

A continuous sequence of flower morphs. At the outer endpoints are the two species Antirrhinum striatum and Antirrhinum pseudomajus. If the in-between shapes ("hybrids") morphologically change over time (for example, within five years), their genetics will also change at the same time (cf. Fig.3), and it is then a transitive process as already described for Diplacus

If this is not the case, then the hybrid hypothesis continues to apply, and the selection theory is the adequate explanation. It is further the selection «value» that dictates the expression of the regulatory proteins.

The arrowheads indicate where anthocyanin is present in the intermediate morphs: calyx tips and flower buds, and nectar guidelines. Pure yellow striatum morphs do scarcely show this trait. Anthocyanin can only be shown in the floral tissues when a subordinate cascade of enzymes and transcription factors are functionally active. If this pathway is down-regulated or not functionally, one cannot detect any dark bluish-red or yellow pigmented floral parts. 

At least in some floral parts (calyx tips, buds), this process has to be upheld. One should also know the reason why some tissues are pigmented only partially.

Further, the flowers bloom gradually with this color, in between stages are «flitting» during the blooming time of individual flowers.

The author sees in this phenomenon a high agreement with that what Diplacus also shows. 

Therefore one should record the life history for such morphs that are in a  between stages to know the reason for only partial pigmentation of floral parts in some cases.

One should also tag permanently individual plants and repeatedly sample different colored parts of its flowers during at least three years. 

It would also be good to have a reference genome to rely on. There is an indication of the many authors who have recently studied this system and are still investigating them. see:

Evolution of flower color pattern through selection on regulatory small RNAs*; Bradley et al., Science 358, 925–928 (2017)

 - The author himself only wants to make comparable observations here and not go deeper into the matter of Snapdragon!. - *In any case, he can not understand precisely what a "... selection of regulatory small RNAs" could be. Selection and molecular regulatory mechanism are both managerial. - It's time for the scientific community to omit one, one device is thoroughly enough.

r.b. 12-16-18

Update June 26, 2019

The likelihood that this is a Diplacus-like analog system has increased significantly with this year's check-up. The system is extremely dynamic. A. striatus transforms into A. pseudomajus within six years. There are local swarms of individuals that are changing. The locality of any swarm moves from year to year up to the valley by 60-200 meters uphill. Behind the swarm, one can count over 95% of A. pseudomajus plants. In front of the swarm, there is a smooth transition. Although Toses is still outside the swarm line (dashed in purple in Fig. 1), 

the individuals there are also swarmed (Fig. 6:)They multiply on the warm masonry (heat island). They are perceived by the locals as weeds and are eliminated in piles. - These statements are valid with an error probability of 30%. By 2020, far more meaningful insights can be gained.


 Fig. 3:

Swarm locations along Eje Pirenaico road between  July 2013 (see Google street map) and 2018 and 2019 check-ups.

Fig. 3a:

Swarm location along Eje Pirenaico road in 2019

A year before nothing similar could be seen here.


Fig. 4:

Two plants (A, B) along GIV-4016 road prominent in rapid transition between 2018 & 2019. (Error probability high because the plants were not priorly be tagged). Swarm location in 2018.

Fig. 5:

Swarm locations along GIV-4016 road between  July 2013 (see Google street map) and 2018 and 2019 check-ups. Prognostic location for 2020 (2020?).

Fig. 5a:

Swarm location 2019 situated 12 m above GIV-4016 road, quad-copter footage.


 Plant  individuals in early transition in Toses


The figure shows the first evaluation of photographically determined data of 104 plants. The lab values determined with the help of the Photoshop program. The cohorts are grouped along a trajectory from A. striatus via transitive forms to A. pseudomajus. The arrowheads point in the direction of the assumed evolutionary development. A flower in transition (inlet middle) may change its color value during the flowering period (∆E). The properties shown are all indications of a transitive change of the flowers in the "hybridization zone."