I believe these are the Himalayan variety -- those invasive bastards we've come to love. They're tastier than the native variety (Rubus ursinus, which has got to be Latin for the bush of the bear? In other words, only bears like to eat them.)
A biologist from the Trust's Natural Resources department said she would not recommend eating anything that grows wild on the Presidio. She knows the soil hazards here -- not only what's leftover from the military, but natural toxins like those found in serpentine. But clearly the wild food foragers don't agree. I pick and eat blackberries - and we certainly ate them all the time as kids -- to no ill effect. It's only a matter of braving the thorns and steep hills and shirt stains.
It's an invasive species, so maybe you won't feel guilty picking a few bunches. The edible root is long and white, but much tastier than the red ones you buy at the supermarket. For a better look at the plant's flowers, see below.
Also in that area was a heap of miner's lettuce that was ready to eat. (Claytonia perfoliata.) Gold Rush miners ate this leaf because it was so packed with vitamins that it could stave off scurvy. It's one of the native plants that the colonizers actually exported back to Europe, they found it so tasty and healthy and easy to grow. (I've even seen it sprout up near Baker Beach.)
In terms of cuisine, the Presidio has a lot to offer. Wild Mustard, Bermuda buttercup, and even yes, the Ice Plant fruit! (More here.) I also stumbled on the wild foods of the Tennessee Hollow Watershed. I think it might be a good time for some salad.
|ice plant flower - no fruit yet|