At first glance, the casual observer would think a pinellia is from the same genus as arisaemas. They have the same jack-in-the-pulpit structure to the inflorescence, so why not? Here are a few hints (from a non-botanist):

1. Pinellias never have more than one seed per fruit.
2. The Pinellia seedhead flops down on the ground to disperse the seeds, which are still green when ripe.
3. The Pinellia flowering stem has no leaves. The leaves arise directly from the tuber. (Yes, some arisaemas do this, too.)
4. The Pinellia spadix is fused to the back of the spathe for some distance.
5. Pinellias bloom several times in each growing season.
6. All Pinellias are monoecious (ie, male and female flowers on the same inflorescence).
7. Pinellias don't get as much respect as Arisaemas, and tend to be cheaper.

There are four species in cultivation and in the trade in the US and Europe:

• Pinellia cordata
• Pinellia tripartita
• Pinellia pedatisecta
• Pinellia ternata

Please do yourself a favor and DO NOT grow P. ternata in the ground. If you'd like to grow it, keep it in a well contained pot. Sorry to say, but P. ternata is close to being the purple loosestrife of the aroid world.

So what are the differences between the inflorescences on these species? Funny you should ask. I just happen to have some pictures. Check them out here.

Eric Walton was kind enough to send me a copy of the Chinese species list from the Proceedings of the VI International Aroid Conference held in Kunming, Yunnan, in the summer of 1995. There are no less than seven Pinellia:

P. cordata
P. integrifolia
P. pedatisecta
P. peltata
P. polyphylla
P. ternata
P. yaoluopingensis

Eric also sent me an abstract of a paper on Pinellia presented at the conference by Li Li of the Beijing Vegetable Research Centre. (do they eat these things???). Mr. Li says there are about 10 species in the world, primarily China, Japan, and Korea. In China there are 8 species and one form. In addition to the names above, he also lists P. zhiguiensis and P. ternata f. angustata, plus P. tenore as a new species. He further proposes that P. yaoloupingensis, zhiguiensis, and the ternata forms are polyploid. P. peltata and integrifolia are described as being relatively primitive, whatever that means (scholarly help is welcome). He does not mention P. polyphylla; if I include it I come up with 9 species instead of 8.