Friday Seeds & germination requirements for Viburnum species

This fall I collected for the first time fruits of Viburnum acerifolium (maple-leaf Viburnum) and Viburnum rafinesquianum (downy arrow-wood Viburnum).

Surely, I was curious to see how the ‘seeds’ (endocarp + seed) are looking but how about their germination?
There are contradictory statements on the web; some say they first need a cold stratification, others say warm. It’s good to clarify this because I like to provide reliable info.

So, back to the books ;)

Viburnum acerifolium pits (endocarp+ seed)

Viburnum rafinesquianum pits

I like Baskin & Baskin: Seeds – Ecology, Biogeography, and Evolution of Dormancy and Germination (2014) because besides giving results from their own experiments, there are citations of hundreds of other articles on germination (of course, in some cases things are not always clear).

And, the warm stratification is the winner!
These Viburnum spp. have deep simple epicotyl morphophysiological dormancy and the germination requirements are: warm/moist stratification period (during which roots emerge), followed by a cold/moist period (after which the shoots grow).
In translation, if sown in late summer they will show up the next spring; otherwise they will germinate complete in the second spring after sowing.

On the same list are many other Viburnum species like: alnifolium, betulifolium, cassinoides, dentatum, dilatatum, lentago, opulus, parvifolium, prunifolium….Those who don’t have access to the book can read here a very short but conclusive summary regarding Viburnum acerifolium germination:
http://www.bioone.org/doi/full/10.1674/0003-0031%282005%29153%5B0232%3AEDIVAC%5D2.0.CO%3B2

Also another summary here:
https://www.researchgate.net/publication/267996605_Overview_of_seed_dormancy_in_Viburnum_Caprifoliaceae