North America Native Plant

Fall Tansyaster

Botanical name: Machaeranthera asteroides var. lagunensis

USDA symbol: MAASL

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Machaeranthera lagunensis D.D. Keck (MALA)   

Fall Tansyaster: A Rare California Native Worth Knowing About If you’re passionate about California native plants, you might have stumbled across the intriguingly named fall tansyaster (Machaeranthera asteroides var. lagunensis). This little-known perennial forb is one of those plants that makes native plant enthusiasts do a double-take – not because ...

Rare plant alert!

Region: Conservation status by state

Status: S5T2T3Q: Status is uncertain but is somewhere between the following rankings: Uncertain taxonomy: ⚘ Subspecies or variety is imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘ Subspecies or variety is vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals. ⚘ Secure: At very low or no risk of extinction in the jurisdiction due to a very extensive range, abundant populations or occurrences, with little to no concern from declines or threats. ⚘

Fall Tansyaster: A Rare California Native Worth Knowing About

If you’re passionate about California native plants, you might have stumbled across the intriguingly named fall tansyaster (Machaeranthera asteroides var. lagunensis). This little-known perennial forb is one of those plants that makes native plant enthusiasts do a double-take – not because it’s flashy or dramatic, but because it’s genuinely rare and represents a unique piece of California’s botanical heritage.

What Makes Fall Tansyaster Special?

Fall tansyaster belongs to the vast sunflower family (Asteraceae) and is classified as a forb – essentially a soft-stemmed, herbaceous plant that lacks the woody tissue of shrubs and trees. This perennial plant represents a distinct variety that has evolved specifically within California’s unique ecosystems.

The plant is also known by its scientific synonym Machaeranthera lagunensis, though the currently accepted name is Machaeranthera asteroides var. lagunensis. Don’t worry if that’s a mouthful – even botanists sometimes trip over these lengthy Latin names!

Where Does It Grow?

This fall tansyaster is exclusively native to California, making it a true Golden State endemic. Its limited distribution is part of what makes this plant so special – and so concerning from a conservation standpoint.

A Word of Caution: Rarity Matters

Here’s where things get serious, fellow gardeners. Fall tansyaster carries a conservation status of S5T2T3Q, which indicates some level of conservation concern. While the exact meaning of this particular code isn’t clearly defined, any plant with this type of designation deserves our respect and careful consideration.

If you’re considering growing fall tansyaster, please ensure any plant material comes from responsible, ethical sources. This means:

  • Never collect plants or seeds from wild populations
  • Source only from reputable native plant nurseries
  • Verify that any purchased plants were propagated, not wild-collected
  • Consider participating in conservation efforts rather than personal cultivation

The Reality of Growing Rare Natives

Unfortunately, detailed growing information for fall tansyaster is quite limited – which is often the case with rare native varieties. We know it’s a perennial forb, but specifics about its preferred growing conditions, care requirements, and garden performance are not well-documented in horticultural literature.

This lack of information isn’t necessarily a drawback; it’s simply the reality of working with genuinely rare plants that haven’t been extensively studied or cultivated.

Better Alternatives for Your California Native Garden

If you’re drawn to fall tansyaster but concerned about its rarity status (as you should be!), consider these more readily available California native alternatives from the same family:

  • California aster (Symphyotrichum chilense)
  • Aromatic aster (Symphyotrichum oblongifolium)
  • White-flowered aster species
  • Other Machaeranthera species that are more common

These alternatives can provide similar ecological benefits while allowing you to garden with a clear conscience about conservation impact.

Supporting Conservation Efforts

Rather than trying to grow fall tansyaster in your home garden, consider supporting conservation organizations that work to protect rare California natives in their natural habitats. Your local native plant society, botanical gardens, or conservation groups often have programs dedicated to preserving species like this one.

Sometimes the best way to appreciate a rare plant is to ensure it continues to thrive where it belongs – in the wild, contributing to California’s irreplaceable natural heritage.

The Bottom Line

Fall tansyaster represents the fascinating diversity of California’s native flora, but its rarity status means it’s not a plant for casual cultivation. If you encounter this species in the wild, consider yourself lucky to witness a piece of California’s unique botanical story. And if you’re passionate about native plants, channel that energy into growing and promoting more common species that can provide similar benefits without conservation concerns.

After all, the best native gardens are those that support both local ecosystems and conservation efforts – and sometimes that means admiring rare beauties from a respectful distance.

Fall Tansyaster

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Asterales

Family

Asteraceae Bercht. & J. Presl - Aster family

Genus

Machaeranthera Nees - tansyaster

Species

Machaeranthera asteroides (Torr.) Greene - fall tansyaster

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA