Status: Native
Synonyms:
None
Asclepias latifolia is the only milkweed in the Gila Wilderness with leaves that are
several centimeters wide, about half as wide as they are long. The veins of the leaves
are conspicuous and the leaf apices are frequently mucronate. The flowers, which tend to hide from view, are axillary and greenish white. The pedicel to the fruit (a follicle) is sharply bent (deflexed.)
A common feature among the milkweeds (the former Asclepiadaceae) as well as many of the Moraceae, the Lactuca like plants of the Asteraceae, the Euphorbiaceae, and the Papaveraceae is the presence of laticifers. These vessels contain a mix of substances, frequently alkaloids as in Papaveraceae or terpenoids as in the Euphorbiaceae and others, that are often poisonous and deter herbivory. The composition of the latex differs among the families, as does the distribution of the laticifers within the stems in the plants of the different families. Even the structure of the laticifers can vary from a single long cell to many cells between which portions of the cell walls have dissolved (articulated laticifers). In Asclepias there are toxins which target the conduction system of the heart (cardiac glycosides). In Asclepias latifolia, the laticifers are distributed throughout the stem. In other genera, such as Lactuca the laticifers are restricted to discrete areas within the stem. On cross section of a milkweed stem, the laticifers appear gray or black dots because the milk is opaque to light transmission in light microscopy.
Please click on an image for a larger file.
Asclepias latifolia, photo Russ Kleinman, Silver City, June 17, 2007
Asclepias latifolia, closeup of flowers, photo Russ Kleinman, Silver City, July 23, 2009
Asclepias latifolia, follicles (note deflexed pedicels), photo Russ Kleinman, Ridge Road near Tyrone Ridge Access cutoff, October 8, 2009
Asclepias latifolia, follicle measured (note deflexed pedicel), photo Russ Kleinman, Ridge Road near Tyrone Ridge Access cutoff, October 8, 2009
Asclepias latifolia, closeup of leaf, photo Russ Kleinman, Ridge Road near Tyrone Ridge Access cutoff, October 8, 2009
Asclepias latifolia, immature follicle opened, photo Russ Kleinman, Ridge Road near Tyrone Ridge Access cutoff, October 8, 2009
Asclepias latifolia, macro of seeds within follicle, photo Russ Kleinman, Ridge Road near Tyrone Ridge Access cutoff, October 8, 2009
Asclepias latifolia, stereoscopic view of stem cross section, photo Russ Kleinman, Pinos Altos, July 12, 2022
Asclepias latifolia, photomicrograph (compound scope) of stem cross section, photo Russ Kleinman, Pinos Altos, July 12, 2022
Asclepias latifolia, higher power photomicrograph of stem cross section, photo Russ Kleinman, Pinos Altos, July 12, 2022
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