Key to Xanthium
View taxon page for Xanthium
(For a list of species in Xanthium, use the above link.)
Jepson Manual glossary definitions can be seen by moving your cursor over words underlined with dots.
1. Nodal
spines 0;
leaf Organ arising from a stem, generally composed of a stalk (petiole) and a flat, expanded, green, photosynthetic area (blade); distinguished from a leaflet by the presence in its axil of a bud, branch, thorn, or flower; sometimes with lateral, basal appendages (stipules); either simple (toothed, lobed, or dissected but not divided into leaflets) or compound (divided into leaflets).
blade Expanded portion of a leaf, petal, or other structure, generally flat but sometimes rolled, cylindric, wavy, or cupped.
ovate Egg-shaped (i.e., widest below the middle) in two dimensions (i.e., in one plane), as a leaf.
to
deltate More or less equilaterally triangular, with the corners rounded or not.
, pentagonal, or nearly round, toothed, sometimes
palmately lobed, abaxially minutely coarse-hairy, green
..... X. orientale 1' Nodal spines present, each generally with 3 divergent branches, 15–30+ mm, golden; leaf blade lance-linear or ±
lanceolate Narrowly elongate, widest in the basal half, often tapered to an acute tip.
to ovate,
entire Having margins that are continuous and smooth (i.e., without teeth, lobes, etc.).
or
pinnately few-toothed or -lobed, abaxially densely
strigose With stiff, straight, sharp, appressed hairs.
, gray to white
..... X. spinosum
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