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Tree Flowers

Dirty trees 

 crab,  silver maple, catalpa, Callery pear,
magnolia, dogwood, sycamore, oak

Flowering crab (Malus species and hybrids, family Rosaceae) is a popular horticultural tree. It abundantly produces showy flowers, and little apples (pomes) that are eaten by robins. Not all of them though.

crabapples on parking lot
Crabapples litter a parking lot in Marion Ohio. March 19, 2009

Crabapples in parking lot, Marion, Ohio. March 19, 2009.

Silver maple is a fast-growing giant, common both in the wild and as a street tree. It flowers before the leaves emerge. The species is monoecious, producing wind-pollinated unisexual flowers in separate staminate and pistillate clusters. After the pollen has been shed, the staminate fowers are shed. In early April these grace the pavement in Columbus, Ohio.  

silver maple sidewalk
Silver maple flowers litter sidewalk in Columbus, Ohio. April 4, 2009.

silver maple staminate flowers
Silver maple staminate flowers. Columbus, Ohio, April 4, 2009.

Showy catalpa (Catalpa speciosa, family Bignoniaceae), a native of the southeastern U.S. shows up here as a popular street, lawn and park tree that produces abundant pretty white flowers in branched clusters in late spring. Its fruits are long capsules which have earned catalpa an alternative common name --cigar tree. Well, it seems like the trees must have seen some "no smoking" signs, because they're dropping their cigars all over the ground!

catalpa fruits adorn driveway
Shed catalpa fruits enhance a driveway in Columbus, Ohio. April 5, 2009

catalpa capsules
Catalpa capsules. April 5, 2009. Columbus, Ohio.

Catalpa seeds are winged for wind dispersal. They superficially (and functionally) resemble maple samaras.  The samaras however are single-seeded fruits, not seeds from within a fruit as are these catalpa seeds.

catalpa seed
Catalpa seed. Aprl 5, 2009. Columbus, Ohio.

Callery pear (Pyrus calleryi, family Rosaceae) is a too-widely planted street tree that flowers abundantly in mid-April. The petals carpet the roadside.

Callery pear
Callery pear. Columbus, Ohio. April 18, 2009.

pear petals
Callery pear petals. April 18, 2009. Columbus, Ohio.

Magnolia (Magnolia species, family Rosaceae) produce flowers with especially large petals, and many of them. They decorate the lawns and sidewalks in early spring.

Magnolia sheds petals. April 18, 2009. Columbus, Ohio.

The petals contrast well with the lawn.

magnolia petals
Magnolia (not dogwood) petals. April 18, 2009. Columbus, Ohio.

In late April, American sycamore (Platanus occidentalis, family Platanaceae) begins to flower. It is a wind-pollinated monoecious tree that produces globose unisexual heads of many tiny flowers. Pollen release occurs as the stamens drop off the trees. The small but numerous stamens litter the ground.

American sycamore stamens
American sycamore stamens. April 30, 2009.

The American sycamore staminate heads are shed after the stamens drop. Red maple trees are also flagrantly disregarding local ordinances against littering!

sycamore staminate capitulum
Sycamore staminate capitula and last year's achenes, plus red maple samaras.
May 9, 2009. Columbus, Ohio.

Along some streets in the Clintonville neighborhood of Columbus, various members of the red oak group of trees, including northen red oak, Shumard oak, and pin oak, are common roadside trees. Judging by the occurrence nearby of known Shumard oaks, and the appearance of these young leaves (intermediate lobe depth between pin oak and northern red), these appear to be Shumard oaks linung the street.

oak twig and staminate catkins
Shumard oak twig and staminate catkins May 9, 2009. Columbus, Ohio.

In early May, oaks flower. Oaks, like many trees, are monoecous and wind-pollinated, and produce extremely abundant tiny staminale (male) flowers in drooping catkins. These are dropped after the pollen has been sent into the breeze (and hopefully into the waiting arms ...I mean stigmas ...of pistillate flowers).

oak catkins
Oak staminate catkins. May 9, 2009. Columbus, Ohio.

Flowering dogwood (Cornus florida) produces small, inconspicuous flowers. What? Huh? Hello? Isn't flowering dogwood the understory tree with big showy 4-petaled blossoms ...a tree that people like to have in their lawns because the flowers are so beautiful?

Flowering dogwood in an urban front yard in Columbus, Ohio. May 9, 2009.

Almost. The big flower-like things are actually clusters of several small flowers. What look like 4 petals are 4 petal-like appendages called "bracts." The serve the same function as petals --to attract pollinators. Here's a closeup of a dogwood flower cluster taken 4 years ago.

dogwood explained
Dogwood flower cluster. May 5, 2005. Columbus, Ohio.

OK. now that we've gotten that straight, let's celebrate the petal-like bracts that these trees are distributing like confetti.

dogwood bracts and oak catkins
Dogwood bracts and oak catkins. May 9. 2009. Columbus, Ohio.