Sunday, December 28, 2014

The Fruit Explorer Encounters Dates, Part 1 of 2

I go to Trader Joe's maybe three times a month, but you have not read of my buying any fruit there. In fact, the fruits reported on in these e-mails rarely even make an appearance at Trader Joe's. In short, despite Trader Joe's offbeat ambience, when it comes to fruit it is very mainstream and unadventurous. For this reason, Trader Joe's has played no role in these e-mails. Until now. While strolling through Trader Joe's, I came across Medjool dates, and I snapped them up. 


               

The term "date" comes from the Greek word for finger, dactylos. Apparently someone thought that dates resembled fingers; I don't see it, but maybe I'm looking at the wrong kind of date. To me dates look more like a big toe. You have previously encountered "dactyl" in "pterodactyl," which comes from the Greek words for wing (pteron) and finger. [Evolution has taken three paths to fashion wings from the basic issue vertebrate forelimb. The bones from an arm are used to construct a bird wing. The bones from a hand are used to construct a bat wing. (Bats are in the order Chiroptera, from the Greek words for hand and wing, which we see in chiral molecules and chiromancy (palm reading).) The bones from a finger are used to construct a pterodactyl wing. These three types of wings are, naturally enough, called arm wings, hand wings, and finger wings. Isn't evolution a gas? See the pictures below to see how to support a wing from these three types of bones. For a pterodactyl you can see how the pinky is greatly extended, and the wing is supported by this elongated finger. You can also see the vestigial fingers. Vestigial for flying, that is; it is thought that some pterodactyls walked on all fours when on the ground. For illustrations of fossilized pterodactyl tracks that show the prints of both the forelimbs and the hind limbs, see, David M. Unwin, The Pterosaurs from Deep Time, 2006, pp. 211, 213; the last picture below is an artist's conception scanned from p. 217. There is a lot more material here, but since I am not the Pterodactyl Explorer, I will get back to the topic.] 

   
   
   
            
   

Dates have numerous health benefits, surveyed at https://www.organicfacts.net/health-benefits/fruit/health-benefits-of-dates.html, including being effective against night blindness. Dates are very rich in sugar, with a date providing 66 calories, so dates are a good food for those who want to gain weight. Also, "The nicotinic content in dates makes them an excellent cure for intestinal disturbances," according to https://www.youtube.com/watch?v=0dcYY1hENhM. (Comment on weight gain. I weighed 182 when I retired in December 2013 and 168 about a year later when I started fruit exploring. Since then, I have eaten the same except for adding fruit, and my weight has gradually increased to its current 175.)


   


Dates are one of the few crops that survives in desert conditions, and Bedouin wealth traditionally was measured in camels and date palms. (In Egypt a greasy old Arab offered Mei-Mei forty camels for her daughter, Mei-Ling. Mei-Mei haggled but couldn't get him to come up on the offer, so she rejected it.)

      

It is a mark of the distinctiveness of the palm tree that, even though most of us have little experience with it, it is one of the few trees that we can identify on sight despite its wide variation. Since the palm is wind-pollinated, the flowers are massive but otherwise inconspicuous since they don't have to attract pollinators. The female flowers (pictured on the left) and the male flowers (pictured on the right) are on different trees, which leads to a curiosity of date palm farming. It would be uneconomic for a date palm plantation to devote half of its trees to the non-producing males, so the trees are almost all female. The preponderance of female trees, however, means that wind pollination will not get the job done. Thus, manual pollination is required; see https://www.youtube.com/watch?v=L27bMQirY60, though the mechanized grower pollinates by machine, see https://www.youtube.com/watch?v=sN3UFpJ6ps0. You might wonder where the pollen comes from. Because of the inherent inefficiency of wind pollination, one male tree produces enough pollen to service fifty female trees. Therefore, only a few male trees are needed when the more focused manual pollination is used. The central leaves of a date palm are almost upright, whereas the peripheral leaves arch outward and downward, making the date palm tree look like it has a punk haircut; you can see this in the thirteenth picture. (Leaf and frond are synonyms for palms.) Other pictures give a sense of the variety of palm trees. A botanical curiosity is that palms are among the few monocot trees in the U.S.; the only others are in the lily family, e.g., the Joshua tree.


    
                                                      


[Continued in Part 1]