Excerpts from Jim Conrad's
Naturalist Newsletter

from the January 25, 2015 Newsletter issued from Río Lagartos, on the north-central coast of Yucatán, MÉXICO
ACACIA CALIFORNICA

This week along the road leading into Río Lagartos a broadly spreading tree was prettily abloom with snowy-white flowers, as seen below:

ACACIA CALIFORNICA ssp. PRINGLEI, flowering tree

The flowers were tiny ones densely packed in fuzzy, white spikes such as those shown below:

ACACIA CALIFORNICA ssp. PRINGLEI, flower spikes

Below, you can see how the individual flowers were arranged in whorls along each spike's rachis:

ACACIA CALIFORNICA ssp. PRINGLEI, individual flowers

That picture also shows that from each flower arise many stamens -- more than ten -- and they're not united at their bases. When a flower exhibits these features, automatically the big genus Acacia comes to mind, and these are classic acacia flowers. However, it's a little unusual for acacia flowers to be arranged in spikes instead of spherical heads Also, the tree's leaves aren't at all typical of most acacias. Normally acacia leaves are twice-pinnately compound, composed of so many small leaflets that the whole leaf gives a diffuse, feathery impression. This tree's leaves were twice-pinnately compound, but the leaflets were few in number and of a fair size, as you can see below:

ACACIA CALIFORNICA ssp. PRINGLEI, leaf

However, when identifying plants, details of flower structure normally figure more importantly than vegetative features, so to begin the identification process with this species first I checked to see if an acacia with flowers in spikes and bearing such curious leaves was listed for the Yucatan. And one was: ACACIA CALIFORNICA ssp. PRINGLEI.

At least, that's the name used by CICY, the Centro de Investigación Científica de Yucatán, and usually they're up to date with their taxonomy. However, most authors seem to call it Acacia pringlei, Vachellia pringlei, or Vachellia californica ssp pringlei, so the scientific community is unsettled as to the name. And nobody offers a decent English name, probably because the tree occurs only in Mexico's arid lands, from northern Mexico to here. The Maya call it Ts'iul che'. Since this species is not well represented on the Internet, here I provide more details.

First, its leaflets are shiny and hairless below, and notched at their tips with tiny "mucros" occupying the notch center, as shown below:

ACACIA CALIFORNICA ssp. PRINGLEI, glabrous leaflet undersurface

The leaf's petiole is curiously channeled and segmented, with a conspicuous gland near the base, as shown below:

ACACIA CALIFORNICA ssp. PRINGLEI, petiole with gland

Short, sharp, woody "stipular spines" arise next to some buds, as shown below in a picture also giving another view of the gland on the petiole:

ACACIA CALIFORNICA ssp. PRINGLEI, stipular spines and petiole gland

The tree is formed of several blotchy, whitish stems, as shown below:

ACACIA CALIFORNICA ssp. PRINGLEI, trunks

Acacia californica ssp. pringlei is uncommon here, though other individuals have been seen, which were smaller and less spectacularly flowering than this one. What a bonanza this blossoming must be for pollinators beginning to feel the dry season's pinch as nowadays many flowering plants just dry up.