These were photographed last week. The yellow flowered plant is a multitrunked tall shrub. The white flowered plant is herbaceous.
Thank you. My photos do appear consistent with B. crassifolia, which I have read is common in much of Mexico.
Thank you. The inflorescence is similar, though a quick search failed to find a good match. I'll keep looking.
Thank you Axel. I've looked at a fair number of Tournefortia images as well as related Heliotropium and many are close but none has quite the same detail wrt flower and what I take to be sepal.
The Heliotropioideae subfamily (Heliotropium, Tournefortia) is strongly under-documented, there are many species without a single photo on the internet. Check Tournefortia arborescens for example which is a quite similar plant, although it has shorter sepals and more veins per leaf. Anyways, the direction may be correct, but you will probably not find out which species it exactly is due to the lack of available information about these genus.
Thank you. Yes, I believe that you (and Uncle Tom) have me on the right path. I have a lead on someone who is familiar with Mexican coastal flora (hopefully including these genera).
You can get more other species in your search results if for this one you rule out argentea by including in your query -argentea (minus sign before the word). That works in the search engines and on flickr. For instance, I saw some Tournefortia densiflora that didn't look totally wrong.
Thank you, Wendy. T. densiflora images aren't the best, but you are quite right, they look pretty close to my plant. I downloaded the original description but unfortunately Google Translate doesn't do a good job on Latin. 5. TOURNEFORTIA DENSIFLORA. Nobis. Coll. H. Gal. No. 1274.) Caule fruticoso flexuoso subangulato glabriusculo laevi, foliis subsessilibus obovatis in petiolum attenuatis, supra asperrimis glabriusculis, subtus pubescentibus scabris, cymis bifidis coarctatis , spicis densis congestis , calycis laciniis subulatis hirsutis corollam longitudine subaequantibus. — Species affinis Tournefortiae hispidae HBK. Further, a recent Mexican paper appears to subsume this species under T. mutabilis... http://www.ibiologia.unam.mx/barra/publicaciones/floras_tehuacan/F_110.pdf I should be satisfied to leave this as densiflora tentatively.
