{"id":573,"date":"2015-10-26T03:28:52","date_gmt":"2015-10-26T03:28:52","guid":{"rendered":"https:\/\/aphidtrek.org\/?page_id=573"},"modified":"2024-12-28T20:48:07","modified_gmt":"2024-12-28T20:48:07","slug":"capitophorus","status":"publish","type":"page","link":"https:\/\/aphidtrek.org\/?page_id=573","title":{"rendered":"Capitophorus"},"content":{"rendered":"\n

Capitophorus<\/em> van der Goot<\/strong><\/p>\n\n\n\n

This page updated: December 2024.<\/p>\n\n\n\n

For several years I’ve been pursuing better understanding of the native North American Capitophorus<\/em> and also aiming to build out my representation of the adventive species living here. This effort was actually sparked by my first collection of Capitophorus<\/em> on Ambrosia<\/em> way back in 1993, the Ambrosia<\/em> growing as a weed on the streets of Kennewick, Washington. These specimens ran to either C. jopepperi<\/em> or C. shepherdiae<\/em> in the key by Corpus-Raros and Cook (1974), but did not seem to match either very well. Since then I have spent time most autumns looking at the fall migrants of Capitophorus<\/em> on Elaeagnaceae wherever I’ve lived or traveled, trying to find members of our native species in the ocean of non-native C. elaeagni<\/em> and C. hippophaes<\/em>. Then, in June of 2017 I found in southern Oregon a strange, small Capitophorus<\/em> on roadside specimens of the common native weed Iva axillaris<\/em> (Asteraceae; poverty weed). It is similar in general shape and morphology to the thing I call C. shepherdiae<\/em> (see below) when collected on Ambrosia<\/em>, but it has some key differences as well. Collecting Capitophorus<\/em> on Ambrosia<\/em> and Iva axillaris<\/em> has continued since 2017, hoping that a diversity of specimens, plus gathering the rarely seen alate viviparae, would shed light on the species-level separation (or lack thereof) between these taxa.<\/p>\n\n\n\n

Along the way, I had been collecting C. essigi<\/em> at high elevations from its summer host, Aconogonon phytolaccaefolium<\/em>, and guessing that it may host alternate between this plant and Shepherdia<\/em> at lower elevations. This heteroecy seems certain at this point based on my collections (see below).<\/p>\n\n\n\n

Since moving to Colorado in May of 2021 I had a major advancement in my plant taxonomy knowledge that led to new and interesting samples and prompted a quick study of the native Capitophorus<\/em> with clavate siphunculi in western North America. What was this plant identification epiphany? It was two-fold: first, I learned that separation of Elaeagnus<\/em> and Shepherdia<\/em> is very easy based on whether stem leaves are alternate (Elaeagnus<\/em>) or opposite (Shepherdia<\/em>); second, I learned that separation of our two native species of Shepherdia<\/em> was also incredibly easy: S. canadensis<\/em> grows in cool mixed forests, has speckly broad leaves, and a low and broad growth habit, while C. argentea<\/em> foliage looks almost exactly like Elaeagnus<\/em> (except it has opposite leaves), with long pale leaves, and grows in desert canyons and drainages far from the habitats of S. canadensis<\/em>. Previously, I had not studied the distinctions among these plants enough to realize how simple the taxonomy actually was, and had therefore missed the opportunity to better understand all their Capitophorus<\/em> species. This oversight in plant taxonomy had nothing to do with the level of difficulty, but just my lack of adequate study! It teaches me yet again to try harder on my botanizing.<\/p>\n\n\n\n

Armed with this new knowledge and some very fun samples from fall of 2021, I spent some time in December curating and sorting my samples of Capitophorus<\/em>. The results are reflected below and in my slide collection database released in 2022.<\/p>\n\n\n\n

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Species covered below (click on the name to jump to that species):<\/h2>\n\n\n\n