Bowl-tube iris –Iris macrosiphon
Range: Widespread in central California’s coastal range and facing Sierra Nevada foothills; south to Mariposa and Santa Cruz counties; north of the Great Central Valley this species is replaced byI. tenuissima. Near sea level to around 3,000 feet (1 to 1000 m) elevation.
Original collection: Corte Madera, Marin County, California, 1854.
Name: By John Torrey, 1857, for the long floral tube (macro = large +siphon = tube) in these iris.
Key identifying features:
- Long floral tube; 1½ to 4½ inches.
- Spathes narrow, closed, enclosing ovary and lower tube.
- Top of tube abruptly bowl-shaped; petals separate around bowl’s rim.
- Stems unbranched, single or double flowered.
- Plants usually individual, or in small clumps.
Flower color: Wide color spectrum: usually lavender or lilac-purple with a white signal spot and darker veins. Outside the area where originally described (Marin County) sometimes cream, yellow or white. Local populations tend to show variations of a single color pattern.
Habitat: Sunny, open oak and pine woodland sites, grasslands or meadows with filtered or no shade. Replaced by other species in adjacent, more shaded habitats. Clumps develop when seeds from several generations fall in the same plot.
Comments: “Ground iris” is another common name forIris macrosiphon. In some regions, plants growing in full sun often develop short floral spikes, flowers may have very short stems. The name “Long tube iris” is also used, but that name could be applied to any of the five PCI in the long-tube group.
LikeIris tenax in Oregon, this species has two strong fibers that extend along the edges of each leaf. For centuries before European settlement, local California peoples used iris fibers as a source of cordage for thread, string, nets, ropes and other uses.
Iris macrosiphon is widely distributed, comprising a mosaic of many distinctive local populations, each with its own long, separate and unique history. Its range overlaps many other Californian PCI species, and over millennia, these contributed to the genetic makeup of today’s bowl tube iris populations.
In past decades some local populations were assigned their own varietal or subspecific names. ButIris macrosiphon shows so much variation, with features that grade into each other, that no one has yet been able to satisfactorily identify distinct, consistent subgroups.
The picture is further confused by book and magazine articles that used the name “macrosiphon” for misidentified individuals of other long-tube species, especiallyI. fernaldii andI. tenuissima. Sometimes truemacrosiphon is found labeled with some other name, likeIris hartwegii.
InI. macrosiphon, the ovary is almost always well hidden inside the two spathes, and unlikeI. fernaldii orI. tenuissima, the petals and sepals separate close along the rim of a bowl-like swelling at the top of the long floral tube.
It is unclear how far northI. macrosiphon extends in the outer Coastal Ranges into northwest California, particularly in areas where it comes into contact with other long floral tube species likeIris tenuissima and possiblyIris chrysophylla. Note that long, upward-curving style crests, like those of these two species, have not been reported forIris macrosiphon.
