Journal archives for March 2021

March 04, 2021

Confusing comb-burs

It's that time of year when the comb-burs (Pectocarya spp.) are popping. Four of the local species are darn near identical vegetatively; three of them are fairly common locally (northeastern Maricopa County) and one is rare. This observation shows the differences in the fruit of the three more common ones, and this one is of the local rarity, P. setosa.
Some description based on a guide I wrote some time ago:
P. heterocarpa: Tips of nutlets bent slightly forwards. Marginal teeth are not spreading; teeth are fewer to missing on one nutlet.
P. recurvata: Nutlets curved backwards. Marginal teeth on fruit regularly spaced, hooked. This is the most common species of the three locally.
P. platycarpa: Swollen margin. Teeth irregularly spaced, hooked, with fattened base; teeth smaller and more numerous at the tips of the nutlets.
And for a bonus here is its slightly larger cousin, Harpagonella arizonica. Fruit differ from the four-nutlet, x-shaped plan of the pectocaryas.

Posted on March 04, 2021 12:15 AM by stevejones stevejones | 2 observations | 6 comments | Leave a comment

March 24, 2021

Updated resource

Ron Russo's updated guide is now available, and it adds one further creosote bush Asphondylia gall, an apical, scimitar-shaped gall provisionally labeled Asphondylia sp. and named "scimitar-leaf-gall midge". The description: "This midge induces flat-sided, sword-shaped, striated, monothalamous bud galls on creosote bush. These galls are green when fresh but turn brown with age. The laterally-flattened sides are furrowed with shallow ridges. The apex of the gall is usually obtuse, and the whole gall is arched. These distinctive galls are almost all on terminal buds and stand out from normal leaves. Adults have not been reared for identification to species level. Their behavior is likely similar to that of other Asphondylia adults."

Posted on March 24, 2021 03:52 AM by stevejones stevejones | 6 comments | Leave a comment