1. Moon Flowers (Ipomoea alba)
Moon flowers are not particular to Buenos Aires; they are grown in gardens around the world, and indeed I first saw these fragrant, nocturnally blooming relatives of the morning glory in our neighbor Kirk’s garden in DC. Soon after we arrived here, however, we came across a large moon flower vine in a front yard around the block from our house. We noticed that the large white flowers were open in the evening and closed during the day, and so Isabel and I set out to pinpoint the timing of the floral movements. We thought the flowers might open pretty quickly, so we made a plan to visit the plant every half hour, starting at 6 pm. Our first evening, we found five elongate swollen buds that looked like they were ready to go. No action at 6; no action at 6:30. When we returned at 7, however, we were surprised to see a fully expanded flower, so we knew the opening took less than 30 minutes. As we were standing there, all of a sudden another bud unfurled in fast forward — opening to its full expanse in less than 60 seconds! We could hardly believe our eyes! A couple of minutes later, another one did the same thing, this time helped by a puff of wind to expand in under 20 seconds. Over the next few weeks, we would swing by the plant before dinner, in time for the evening show, and came to reliably recognize buds that would open within the next minute or so.
The folding-up the next day is a slower process. We visited the plant every hour starting at 8 am and found that the petals gradually roll in, so that by noon the open flower looks like a tube sock that has just been pulled off a leg. They roll up faster in the sun, and will stay open into the early afternoon on a cool or cloudy day. Each flower lasts only about 15 hours — enough time, presumably, to be visited and pollinated by a long-tongued hawkmoth, though we never saw any hover by.
The precision of the opening time reminded me of Linnaeus’ idea for a floral clock, which was meant to allow a viewer to tell the time, based on fixed opening and closing times of particular species: http://www.bbc.co.uk/dna/h2g2/A5170024
2. Monstera deliciosa – Nature’s Happy Meal
My friend Rudi introduced me to the delightful fruits of Monstera deliciosa, which ripen and fall in the autumn, and provide days of delectation and amusement. The common name of the plant is split-leaf philodendron (also ‘fruit salad plant’), a vine with huge leaves that climbs high up the sides of trees and buildings, and is commonly planted in gardens and parks in Buenos Aires.
The fruits look kind of like elongate green pine cones, covered with hexagonal green tiles. They ripen slowly, starting as the end farthest away from the stem, over the course of about 5 days, all the while emitting a pungent pineapple fragrance that fills the kitchen. The tiles lift off the fruit and fall away (great for arranging into geometric patterns), revealing another set of white hexagons below. This is the soft edible part of the fruit, which you pull off of the tough core and eat; it tastes like a cross between pineapple and banana – delicious, just as the latin name of the the fruit promises! The next day, you’ll have a few more tiles and a little more fruit. You can only eat the flesh below the loosened tiles, so a fruit will last about a week, in daily doses of an inch or two of ripeness.
You have to be careful not to eat the green tiles or the unripe fruit, because they contain calcium oxalate crystals and other substances that can irritate your mouth and throat. (Some plants in the Arum family, to which Monstera belongs, are called ‘dumbcane,’ because ingestion of the plant can literally make you dumb, at least temporarily.)
3. Palo Borracho (Chorisia speciosa)
Palo Borracho is a very common street tree in BsAs, instantly recognizable (depending on the season and age of the tree) by its bottle shape, green spiny trunk, voluptuous pink flowers, and large green mango-sized fruits that open to release puffs of cottony-downy seeds.
4. Samaras on a legume! (Tipuana tipu)
This one is just for the botany aficionados — samaras on a legume! In plant taxonomy class I learned that plants in the pea family have fruits called legumes, which are essentially pea pods — but one of the most common and beautiful street trees in Buenos Aires, the tipa (Tipuana tipu), has fruits that look just like typical maple samaras, with one seed and a wing! I can hardly explain how startling and almost unnerving a sight this is — maybe like seeing feathers on a cow!