Once again, I saw two snakes on my way to check plots for seedlings at Saguaro National Park! This time, they were not venomous (at least, the first wasn’t, the second I’m not so sure), so I stopped to snap some photos with my cell phone (my good camera being too bulky for the trail run to the far plots).
Dangerous or not, they seemed just to be cold and sunning themselves (snakes from other climates would laugh; it was “only” 80 degrees at that point, positively chilly here!), but still gave me a good shot of adrenaline when I came upon them suddenly.
A wide diversity of seedlings has been germinating in the Tucson Mountains, where my research study sites are located, since the monsoon season got seriously under way 10 days ago. Watching the cryptic cotyledons flush out into cagey leaves has me playing plant detective. See how you do – which seedlings can you identify?
I posted in April about the sunbursts of palo verde trees (foothills PV: Cercidium microphyllum, syn. Parkinsonia microphylla, and blue PV: Cercidium floridum, syn. Parkinsonia florida) in full flower. These unique trees have green bark that photosynthesizes like leaves! Well, maybe not quite like leaves – I need to find out more about how they exchange carbon dioxide with the surrounding air. I bet the cells have a slightly different structure. Anyone reading this know?
Anyway, their seedlings germinated in force throughout the Tucson mountains last week, after a 4th of July celebratory rainstorm. These trees produce seed pods much like snow peas you grow in your garden, which is hardly surprising, given that they are in the pea family, and which are edible and taste like peas, but nuttier. Tiny beetles lay their eggs in many seed pods, then hatch out and eat the seeds. They may claim a quarter to a half of the seed crop, according to the seeds I collected and observed beetles hatching from (several thousand seeds from three sites).
The seeds that survive the beetle onslaught are often in pods with siblings, so groups of up to five of these enormous, luminous, hilarious looking seedlings have been germinating in hollows throughout the volcanic slopes of the Tucson foothills. Consider five small seedlings in a space smaller than one tree. Only one can survive long enough to reproduce, clearly. So does this hedge the tree’s bets, or reduce the vitality of all the seedlings? Do trees that produce seeds in pods of 1-2 seeds do better than those dropping pods of four seeds at a time? These would be some interesting questions to investigate.
I have noticed a number of them disappearing, but not as many as I might imagine if the plentiful desert cottontails or ground squirrels were eating the juicy-looking cotyledons. I have game cameras deployed in the foothills, and I am wondering: where do these seedlings go?
It’s like something out of The Amazing Spiderman: as if scorpions weren’t cool (or scary) enough, if you shine a black light on them at night, they glow bright green.
Why? Douglas Gaffin and his fellow scientists in Oklahoma did some experiments with blindfolding scorpions (yikes), then shining lights on them, and watching their responses. They showed that the scorpions reacted to UV light as though the whole rest of their body (the cuticle or outer shell) were detecting the light! You can check out a colorful poster of their findings, or if that’s too dense, read a news article summarizing it.