Last night the night-blooming Cereus bloomed in our area. While Tohono Chul Park and the Cactus Society's park on River Road got all the press, we went looking for wild specimens here in the creosote flats of Picture Rocks. We took off around sun rise, shortly after 5 am. The flowers were still crisp when we started but began to wilt before we go home around 7 am.
We found more than 20 blooming plants and several that took the year off. Most plants do that from time to time - the whole over-ground part of the plant, which is pretty thin to begin with, shrivels up and looks dead. Luckily, a fresh trunk eventually springs from the under-ground tuber and in a couple of years will be ready to bloom.
Most plants had 1 to three flowers, about knee to wast high and hidden within creosote bushes. Their sweet cloying fragrance betrays them and optically they stand out as pale handsized signals even at dawn and even from a distance.
Randy, being a head taller than I, had a definite advantage spotting them after he had the search image down.
A few plants towered above their creosote companions with a whole array of flowers on an antler-like branched system of trunks. Here in the desert, the wild plants seem to max out at around a dozen flowers. Irrigated specimens in parks, under optimal conditions can have more than 20 flowers.
Here are a few notes from Facebook correspondent Larry Ayers: a great drawing by Paulus Roetter, an artist who accompanied George Englemann when Englemann was exploring the US/Mexico boundary. This might be the first visual record of the species we now know as Peniocereus greggii var. greggii, La Reina de la Noche.
Another plate from Englemann's report which shows cross-sections of P. greggii stems, the tuberous roots, and other details
Also, several people from Cochise Stronghold and the Bisbee area have found blooming Queens since mid-May (2016) while the ones here NW of Tucson showed only very small buds. Larry says: Yours (NW Tucson) are var. transmontanus, which I think of as the Sonoran sub-species, whereas the plants down here (Cochise Co.) near the border are var. greggii. The greggii var. greggii plants seem to be consistently earlier to bloom.
Asked if he is aware of any morphological differences between the two subspecies he answered: I think so. Some friends of mine in the Bisbee area have plants which they bought from Tucson nurseries. Transmontanus seems to have larger flowers and stems with more ribs, and the stems are slender compared to var. greggii.