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Arisaema section Decipienta. Here again, we have rhizomes, rooting all over, but plants have a seasonal behaviour. As usual, there is one growing season a year, a pseudostem emerges generally early autumn.
  Figure 13. A. rhizomatum.
 
 
Figure 13. A. rhizomatum.What can be Learned From Arisaema Tubersby Just Looking at Them by Guy Gusman A tuber is most often the first contact one has when getting Arisaema plants from friends or from the trade. Of course, it is not possible to identify a species just with a tuber in one’s hand. Nevertheless, there are some aspects about the tubers which may provide clues to mitigate this uneasiness. For instance, tubers of A. serratum and A. candidissimum are so different that they cannot be confused. A glance at a tuber will often tell you if an obvious mistake was made and, on the contrary, if this tuber may actually correspond to the expected species. Speaking scientifically, the tuber provides some necessary morphological clues for the correct identification, but not sufficient information to provide identification to the species level. A look at the shapes of Arisaema tubers and rhizomes in the different sections may help to illustrate these points to the reader. Unfortunately, the external colour of the tubers is often the result of the way they were stored, away from light or not. On the contrary, inside, most tubers are creamy white and rhizomes are often purple. You can learn more about Arisaema in the new book The Genus of Arisaema. A Monograph for Botanists and Nature Lovers by Guy and Liliane Gusman. Click on the thumbnails for larger images and more information. Images with rulers indicate size in centimetres. All images Copyright © 2003 by Guy Gusman. Arisaema Sections: * Anomala * Arisaema * Clavata * Decipienta * Dochafa * Fimbriata * Flagellarisaema * Franchetiana * Lobata * Nepenthoidea * Pedatisecta * Sinarisaema * Tenuipistillata * Tortuosa Anomala In this section, all species are evergreen and aseasonal. Petioles and peduncles emerge from a rhizome rooting all over. Roots are present everywhere along the rhizome. Usually the rhizome is internally colourd violet-purple. Its length may vary and, sometimes, very short rhizomes have been confused with tubers, such as in A. balansae. When leaves have been cut off for shipping, petiole and peduncle remains are still present. Figure 3. A. victoriae has so short a rhizome that it could easily be confused with a tuber.Figure 1. In A. filiforme , peduncles and petioles arise continuously from the rhizome but independently one from the other. Figure 2. A. petelotii has huge rhizomes. Arisaema Three different types of tubers are encountered: 1. The tuber is annulated, more or less elongate to ovoid in shape. The roots only surround the central shoot (Figures 4, 5, 6, and 7). Figure 4. Elongate tuber of A. speciosum. Figure 5. A. dahaiense has the same kind of tuber.Figure 6. In A. galeatum, the tuber is more ovoid. Figure 7. Compare the tubers of A. galeatum (left) with A. speciosum (right). 2. A second shape found in section Arisaema is the group A. dilatatum, A. elephas, A. wilsonii... where tubers are flattened on both upper and lower sides with many tuberlets soon developing their own roots and becoming independent of the mother tuber. The size may vary from small in A. elephas to huge in A. wilsonii. Figure 8. Tubers of A. dilatatum. Figure 9. The tubers of A. propinquum are not very different from those of A. dilatatum. Figure 10. A. costatum showing the typical, small rounded tuber.3. On the contrary, tubers of A. intermedium and A. costatum are more globose and quite small in comparison with the size of the plant. Clavata Tubers are subglobose. They look quite different if dry or when in growth. Figure11. A. clavatum. Even flowering-sized tubers are rather small. Figure 12. As pointed out by Jin Murata, many accessory buds develop in the leaf axils of the Japanese A. heterocephalum. These tubers recall those of the group A. yunnanense.Figure 13. A. rhizomatum.What can be Learned From Arisaema Tubersby Just Looking at Them by Guy Gusman A tuber is most often the first contact one has when getting Arisaema plants from friends or from the trade. Of course, it is not possible to identify a species just with a tuber in one’s hand. Nevertheless, there are some aspects about the tubers which may provide clues to mitigate this uneasiness. For instance, tubers of A. serratum and A. candidissimum are so different that they cannot be confused. A glance at a tuber will often tell you if an obvious mistake was made and, on the contrary, if this tuber may actually correspond to the expected species. Speaking scientifically, the tuber provides some necessary morphological clues for the correct identification, but not sufficient information to provide identification to the species level. A look at the shapes of Arisaema tubers and rhizomes in the different sections may help to illustrate these points to the reader. Unfortunately, the external colour of the tubers is often the result of the way they were stored, away from light or not. On the contrary, inside, most tubers are creamy white and rhizomes are often purple. You can learn more about Arisaema in the new book The Genus of Arisaema. A Monograph for Botanists and Nature Lovers by Guy and Liliane Gusman. Click on the thumbnails for larger images and more information. Images with rulers indicate size in centimetres. All images Copyright © 2003 by Guy Gusman. Arisaema Sections: * Anomala * Arisaema * Clavata * Decipienta * Dochafa * Fimbriata * Flagellarisaema * Franchetiana * Lobata * Nepenthoidea * Pedatisecta * Sinarisaema * Tenuipistillata * Tortuosa Anomala In this section, all species are evergreen and aseasonal. Petioles and peduncles emerge from a rhizome rooting all over. Roots are present everywhere along the rhizome. Usually the rhizome is internally colourd violet-purple. Its length may vary and, sometimes, very short rhizomes have been confused with tubers, such as in A. balansae. When leaves have been cut off for shipping, petiole and peduncle remains are still present. Figure 3. A. victoriae has so short a rhizome that it could easily be confused with a tuber.Figure 1. In A. filiforme , peduncles and petioles arise continuously from the rhizome but independently one from the other. Figure 2. A. petelotii has huge rhizomes. Arisaema Three different types of tubers are encountered: 1. The tuber is annulated, more or less elongate to ovoid in shape. The roots only surround the central shoot (Figures 4, 5, 6, and 7). Figure 4. Elongate tuber of A. speciosum. Figure 5. A. dahaiense has the same kind of tuber.Figure 6. In A. galeatum, the tuber is more ovoid. Figure 7. Compare the tubers of A. galeatum (left) with A. speciosum (right). 2. A second shape found in section Arisaema is the group A. dilatatum, A. elephas, A. wilsonii... where tubers are flattened on both upper and lower sides with many tuberlets soon developing their own roots and becoming independent of the mother tuber. The size may vary from small in A. elephas to huge in A. wilsonii. Figure 8. Tubers of A. dilatatum. Figure 9. The tubers of A. propinquum are not very different from those of A. dilatatum. Figure 10. A. costatum showing the typical, small rounded tuber.3. On the contrary, tubers of A. intermedium and A. costatum are more globose and quite small in comparison with the size of the plant. Clavata Tubers are subglobose. They look quite different if dry or when in growth. Figure11. A. clavatum. Even flowering-sized tubers are rather small. Figure 12. As pointed out by Jin Murata, many accessory buds develop in the leaf axils of the Japanese A. heterocephalum. These tubers recall those of the group A. yunnanense.Figure 13. A. rhizomatum.
     
     

Images Copyright © 2003 by Guy Gusman.

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