Another mystery born of jotting down just a common name from my 1982 field guide. When I searched on the name “northwest willow,” I got Salix exigua, which I already drew a couple of weeks ago (common names: sandbar willow, narrowleaf willow, or coyote willow–not northwest willow, according to Wikipedia, but there you are). Hm. My friend Aleks dug up Salis sessifolia, also known as northwest willow, so I happily drew that. I’ll find out when I get home whether it’s what the field guide had in mind.

In the world of fauna, sessile means stationary: a mature barnacle, for example, is in its sessile phase. (Did you know that young barnacles swim freely? True.) In flora, a sessile leaf is one that attaches directly to the twig, without a stalk. So this is a sessile-leaf willow.