Species Information
Kingdom: Plantae
Phylum: Anthophyta
Class: Dicotyledoneae
Order: Gentianales
Family: Apocynaceae
Genus: Asclepias
Species: sanjuanensis
San Juan Milkweed - Asclepias sanjuanensis
Image courtesy of New Mexico Rare Plants
569082
Species Extent (New Mexico)
General Description
Herbaceous perennial; stems from a subterranean woody root crown, 4-8 cm tall, prostrate to ascending; leaves 2-4 cm long, oblong-lanceolate, white tomentulose on leaf margins; inflorescence a terminal umbel with 4-15 flowers; corolla browish purple; follicle 3.5-6.5 mm long. Flowers late April and early May.
Status
Global Rank: G2
State Rank: S2
| Rank Metadata | |
|---|---|
| State Rank: S2 | Rank Changed: 01/26/2024 |
| Rank Reviewed: 01/26/2024 | |
| Reason: Previous assigned rank was S2S3 (by Mitch). The calculated rank is S1. Though additional localities have been found in recent years, there are relatively few individuals and a lot of habitat destruction (Sivinski). S2 would be an appropriate rank, but it may likely be a G3 (Sivinski). See notes in "Population Size." Ventrella agrees with an S2 rank because the species "has become pretty scarce on the Navajo Nation, at least in 2022, when I did surveys at older EOs for this species. We need additional surveys during more favorable moisture years." |
| Ecological Factors | |
|---|---|
| Specificity: Moderate. Generalist or community with some key requirements scarce. | Range Extent: 1000-5000 square km (about 400-2000 square miles) |
| Occurences: 21 - 80 | Population Size: 50 - 250 individuals |
| Area of Occupancy: Estimate based on summed area of current EOs in the Biotics database. Area may be inflated due to locality uncertainty distances, therefore no additional area was added on for new EOs. | Threat Summary: Agriculture & aquaculture - Medium | Residential & commercial development - Low |
State Status:
Observations in Natural Heritage New Mexico Database
Number of Subpopulations: 40
Number of Mapped Locations: 64
Number of Observations: 45
Observation date range: 06-23-1978 to 05-07-2024
External Links
View More Information about this species at:
NatureServe Explorer
New Mexico Rare Plants Website
Environmental Conservation Online System (ECOS)
NatureServe Explorer
New Mexico Rare Plants Website
Environmental Conservation Online System (ECOS)