Transition Studies in Flowering Plants  

by Rolf Baumberger

 

HOME  - Introduction - Diplacus (Mimulus)                                   

There is a more significant discrepancy between what is presented in botanical scientific works as a hybrid system and our findings. 

On the one hand, it is always assumed that two subspecies encounter each other and hybrid forms occur as a result. -  In no case in long-term observations, we could confirm this. 

In doing so, we strictly rely on measurable physical quantities as time, length, color measurement, location,  and gene information. 

It is a red, bird-pollinated small flower of the genus Diplacus, which develops from a large yellow flower on the same plant within 15 to 20 years. The process goes in this way only and does not start in the next generation from scratch again.

The triggering factors are likely to be biotic and abiotic environmental changes. 


Please see the dynamics in the following video clip.  

Movie 1: Summarizes the dynamics of floral color transitions in populations between 1996/97  and 2010.  


Diplacus plant morphs



Fig.1: All kinds of orange to red flowering Diplacus plant morphs that come into question. - The red-flowered Diplacus puniceus (A), D. parviflorus (D), and D. rutilus are well known. Less well known is the variety on Santa Catalina D. «catalinensis» (B). D. «catalinensis» has slender orange-red flowers. 

Incipient morphs

(C) is a variety becoming established on Santa Cruz Island? (E) with its orange colored flowers is a variety that seems to establish above 1000 m in altitude on the Santa Ana Mountains. (F) is already established along San Fernando Pass region.

(More specific features of these morphs will follow sometimes).



Shift of Transition boundaries


In the 60s the transition activity was laying well in Baja California, the coastal and southern part of San Diego County, and also on Catalina Island. The center of transition for Diplacus (Mimulus aurantiacus) shifted more north in the 90s and will be heading to the northern part of Santa Ana Mts along a corridor up to Santa Cruz island in the 2020s. One may find the highest transition activity always in the current (now 2020s) zone. All three incipient morphs mentioned above lie within this zone.