huitztli.

See an image that represents huitztli in the Visual Lexicon of Aztec Hieroglyphs, ed. Stephanie Wood (Eugene, Ore.: Wired Humanities, 2020-present).

tlenamaca, contema yn iacxoyauh, yn iuitz yeheço = He offered incense; he spread out his fir boughs, his bloodied maguey spines (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 8 -- Kings and Lords, no. 14, Part IX, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1951), 81.

uitztontli = a little pointed; uitzpil = a little pointed (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 10 -- The People, No. 14, Part 11, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1961), 113.

Thorns (vitztli) are given as some of the essential items found in the "devil's houses" (Sahagún).
Fray Bernardino de Sahagún, Primeros Memoriales, ed. Thelma D. Sullivan, et al. (Norman: University of Oklahoma Press, 1997), 116.

auh yoã in iehoatl in Quetzalcoatl no tlamaceoaia qujҫoaia, in itlanitz ynjc quezviaia in vitztli, yoan maltiaia iooalnepantla: auh in vmpa onmaltia, in inealtiaia catca, itocaiocan xippacoiã = And this Quetzalcoatl also did penances. He bled the calf of his leg to stain thorns with blood. And he bathed at midnight. And he bathed there where his bathing place was, at a placed name [sic] Xippacoyan (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 3 -- The Origin of the Gods, Part IV, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1978), 14.

Zazan tleino, iluicac ommapilotoque. Uitztli. = What is it that points its finger at the sky? A maguey thorn.
Thelma D. Sullivan, "Nahuatl Proverbs, Conundrums, and Metaphors, Collected by Sahagún," Estudios de Cultura Náhuatl 4 (1963), 132–133.

aҫo oalpanvetzi in jnvitz, in jnmeuh in machcocolhoan, in motechiuhcaoan in mjtzmocavilitivi: aҫo qujmoxotlaltiliznequj, aҫo qujmocueponaltiliznequj in vitztli, in metl in vecatlan: tlallan contlazteoaque in vevetque = perhaps there emerge the thorn, the maguey of thy great-grandfathers, of thy forefathers, which they go bequeathing to thee. Perhaps [our lord] desireth that the spine, the maguey which the old men planted deep in the soil, should sprout, should flower (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1961), 142.

uiztli = espina
Rémi Siméon, Diccionario de la lengua náhuatl o mexicana (Mexico: Siglo XXI, 1996), xxxiv.

in acxoyatl in huitztli = objetos del autosacrificio: ramas de un árbol, espinas de maguey = una metáfora para decir 'autosacrificio' (s. XVI)
Katarzyna Mikulska, "Te hago bandera...Signos de banderas y sus significados en la expresión gráfica nahua," Los códices mesoamericanos: Registros de religión, política y sociedad, coord. Miguel Angel Ruz Barrio y Juan José Batalla (Zinacantepec, Estado de México: El Colegio Mexiquense, 2016), 86..