Observations of the Month: Cattails (Typhaceae)

Common Cattail (Typha latifolia)
https://www.inaturalist.org/observations/15586743
Southern Cattail (Typha domingensis)
https://www.inaturalist.org/observations/15430174

Cattails are widespread in San Diego County, found pretty much wherever suitable wetland habitats are located. Two species, Typha domingensis and T. latifolia, have been documented by voucher specimens in San Diego County. (There are a few unconfirmed reports of T. angustifolia in the county.) Typha domingensis is more common with 119 vouchers compared to T. latifolia with 54 vouchers. On iNaturalist, many observations of cattails are not identified because the characteristics needed to distinguish the species are not apparent in the photos submitted. The observations of the month were submitted by Jon Rebman, curator of Botany at the Nat, to demonstrate what should be photographed to allow accurate identification of Typha species. Take a look at the two observations and you will see that there are several photographs of the plant for each observation. One photograph shows the plant as a whole, another shows the flowering/fruiting spike (including the juncture of the two corn-dog-like structures, which are the male (above) and female (below) flowering spikes), and another shows the inside of the leaf where it clasps the stem. If you are very observant, you will have noted that with T. latifolia there is no gap between the two "corn dogs" (male and females spikes) and there are no brownish glands visible on the inside of the leaf, but T. domingensis usually has a gap between the different sexes of flowers and brownish glands are present on the inside of the leaf. Next time you see cattails in San Diego County, you'll be ready to pull out your phone or camera and snap the photos needed for identification.

Posted on October 1, 2018 01:46 PM by milliebasden