ID requested for Trillium cf. chloropetalum

Max Withers
Tue, 02 Apr 2013 10:18:34 PDT
The latest Jepson Flora treats T. kurabayashii as a synonym of
angustipetalum, without explanation. Freeman's original distinction (below)
seems perhaps a little wobbly, but one would like to know the rationale for
reducing them.

John D. Freeman, Revision of Trillium Subgenus Phyllantherum
27, No. 1 (1975),  1-62,  Stable URL:

The characteristic features of Trillium kurabayashii that distinguish
populations and individual plants from those of T. angustipetalum include
the following: (1) sessile, usually acuminate bracts, (2) longer and wider
sepals, and (3) much wider petals. The length/width ratio of petals of T.
kurabayaskii averages about 4.5 (range 2.7-5.8, based on all available
herbarium material), whereas that of T. angustipetalum averages about 9.0
(range 6.5-11.0 on the same basis). Thus little (if any) overlap exists in
the petal length/width ratios of these two species. The relative
proportions of the androecia and gynoecia are similar in T. kurabayashii
and T. angustipetalum, both with stamens only slightly longer than carpels,
but the anther connectives are slightly more prolonged and the stigmas more
sharply angled at their bases in T. angustipetalum than in T. kurabayashii.

On Tue, Apr 2, 2013 at 11:29 AM, Jane McGary <>wrote:

> Regarding the question about red-flowered Trillium in California's
> Redwood National Park, I recently posted a query about the taxonomic
> status of Trillium kurabayashii, a red trillium from around the
> Oregon-California border commonly grown in gardens here in Portland.
> I learned that the name T. angustipetalum is now applied to
> populations in some parts of California, and CalFlora's website seems
> to imply that T. kurabayashii has been sunk in that name. I am
> growing a red trillium from Tuolumne County (one of the T.
> angustipetalum locales) and several "kurabayashii" from Portland
> gardens. The latter eventually grow larger. I received some very
> interesting private correspondence from Larry Neel, who sent me
> photos of a remarkable number of color variants of both red trilliums
> and T. chloropetalum that he photographed in the wild. It still isn't
> clear to me whether T. kurabayashii is a currently accepted taxon, or
> sunk in angustipetalum, or what the difference between the two is
> other than size and distribution. In any case, these two names cover
> any red trillium that might be in Redwood National Park, and T.
> chloropetalum appears now to be restricted to populations with
> sessile, whitish (greenish, yellowish) flowers and red-mottled
> leaves. The other western white trilliums do not have sessile flowers.
> Jane McGary
> Portland, Oregon, USA
> At 08:30 AM 4/2/2013, you wrote:
> >(Forwarded from the contact form)
> >
> >"Hi, I went camping in the Redwood National Park this weekend, and
> >found a species of red trillium I can't ID. I'd like to send a pic,
> >hoping one of you guys might know what it is. I think it is a Trillium
> >chloropetalum. Thanks Jessica"
> >
> >To see her photo in habitat scroll to the bottom of the Mystery Bulb
> >page
> >…
> _______________________________________________
> pbs mailing list

More information about the pbs mailing list