Excerpts from Jim Conrad's
Naturalist Newsletter

Desert Hackberry, CELTIS PALLIDA

from the April 20, 2014 Newsletter issued from the Frio Canyon Nature Education Center in the valley of the Dry Frio River in northern Uvalde County, southwestern Texas, on the southern border of the Edwards Plateau, USA
DESERT HACKBERRY FLOWERING

The Desert Hackberry, sometimes called Spiny Hackberry, CELTIS PALLIDA, is common in the scrubby forest around Uvalde. A typically zigzagging branch of one about shoulder high, bearing new leaves and flowers, is shown above.

Flowers in the Elm Family, to which hackberries belong, are either unisexual or "hermaphroditic" -- hermaphroditic ones possessing both male and female parts. Hackberry species normally bear both unisexual and hermaphroditic flowers on the same tree, though sometimes the trees are functionally one sex or another. In the above picture the yellowish-green blossoms scattered along the twigs are male flowers consisting of little more than bundles of pollen-producing stamens. However, here and there female flowers do occur, easy to identify because among small and apparently useless stamens rise plump ovaries looking like tiny, green eggs, as seen below:

Desert Hackberry, CELTIS PALLIDA, female flower

In that picture the fuzzy item atop the ovary is the two-lobed style with hairy stigmatic zones for catching pollen from male hackberry flowers. Those stubby, curved, banana-shaped things below the ovary are vestigial stamens. You can see that this flower bears no corolla, and that's a feature of the entire Elm Famil. By fall, the ovary will have developed into a sweet, edible, yellow-orange fruit, a drupe, relished by birds.

In fact, the fruits, along with the densely entangling spiny branches, cause Desert Hackberry to be extremely valuable as wildlife food and cover. It's also useful for erosion control, and because of its dense habit can be useful as a landscape screen or informal hedge.

Desert Hackberry leaves don't grow much larger than what's shown above, so relative to other hackberry species Desert Hackberry leaves are exceptionally small. Though the limb in the picture is spineless, Desert Hackberry often bears slender spines. The side branches of the branch in our picture are spinelike, or "spinescent" -- like stout spines bearing leaves and flowers.

Desert Hackberry occurs throughout tropical America from northern Argentina north to southern Texas, New Mexico, Arizona, and Florida, It's likely to show up in grasslands, brushlands and thickets wherever there's gravelly, well-drained, sandy soil, as in deserts, canyons, washes, foothills, washes and the like.


from the July 27, 2014 Newsletter issued from the Frio Canyon Nature Education Center in the valley of the Dry Frio River in northern Uvalde County, southwestern Texas, on the southern border of the Edwards Plateau, USA
DESERT HACKBERRY FRUITING

Nowadays in the scrub around Uvalde the Desert Hackberries are developing ripe, yellow-orange hackberries, shown below:

Desert Hackberry, CELTIS PALLIDA, fruits & spines

Botanically, hackberry fruits aren't berries. They're drupes, which are fleshy, one-seeded fruits that don't split open when they're ripe, and the seed is enclosed within a stony endocarp. To visualize a seed enclosed within a stony endocarp, think of a peach "seed," which consists of the woody, wrinkled endocarp, which when you break open reveals the actual soft seed inside. The exocarp of the peach is the fleshy part we eat, the same as with hackberries.