Kimberly's focal taxon
From BioDivBorneo2010
Contents |
Zingiberaceae
Introduction
The Zingiberaceae is a large plant family more commonly known as the gingers. They are perennial herbs with rhizomes that can grow either long or short. The rhizomes are usually turned upwards and they grow into either a leafy shoot or an inflorescence. The rhizomes can grow as a sympodium (a series of interconnected rhizomes that arise from the buds near the apex) or as individual stalks. Large clumps of a single ginger plant can be formed by this rhizomatic growth. Gingers have both true roots and rhizomes, but both types of 'root' cells have compounds that give rise to the unique, spicy, aromatic smell well associated with gingers. In the tropics, such as Borneo, some gingers can grow almost continuously because of the constant light and rain characteristic of the area, while others may have slight increase in growth during the rainy season. Some gingers even have a dormant period in which the rhizome may lose all of its leaves and slow or halt growth for a time.
Despite the fact that gingers are commercially important in many forms including as spices, dyes, flavoring, oils and additives to other common products, three species are most utilized and well-know. The two gingers most utilized in cooking are the rhizomes of the common ginger, Zingiber officinale, and Curcuma domestica (tumeric). The third species is Elettaria cardamomum (cardamon), in which the dried seed is used for teas, scents, or flavoring. Beyond these basic uses, the gingers are a fascinating plant with much variety in stem growth, hairiness, flowers, size, leaf coloration, and inflorescence organization. A real stem is often present, but the large visible stem is actually the pseudo-stem, which is formed by the leaf sheaths. A stalk-like protrusion sometimes arises from the stem where the leaf bud forms and, despite the fact that it has been called a 'petiole', it is not actually parallel in structure to the true petioles of other plants. The inflorescence can grow from the ground (called radical), the mid-stem (which is especially striking in Plagiostachys), or at the apex of leafy shoot (called terminal). Most flowers in the inflorescence have both bracts and smaller, more inner coverings called bracteoles. The whole inflorescence also has a more traditional bract. The flowers are highly specialized and bisexual. They have an inferior ovary, with a corolla that has a narrow tube with three sub-equal corolla lobes. The upper lobe is usually shaped like orchid lip, but botanically it is two or three modified sterile stamens (not a true petal like in orchids). The fruits are dry or fleshy capsules and can dehisce by way of three slits. The fruits may also be indehiscent. The seeds are dark brown to black with a colored aril coating or fleshy jacket covering and most are strongly aromatic. [1]
For this Focal Taxon study, 12 individual gingers were looked at in detail throughout the multiple locations of the course, with characteristics relating to reproductive organ coloration, stem and leaf appearance, size, vein organization, inflorescence structure and petiole-like structures recorded. Data was then used to create a phylogentic tree depicting the possible relationships between these individuals. Whenever possible, the individuals were identified to genus and/or species. When unknown, a morphotype is given instead.
Genus: Alpinia
Two gingers were tentatively identified in the Alpinia genus.
Genus: Costus
One ginger was tentatively identified in the Costus genus.
Genus: Etlingera
Two gingers were tentatively identified in the Etlingera genus.
Genus: Plagiostachys
One ginger was tentatively identified in the Plagiostachys genus.
Genus: Unknown
Five gingers are of unknown genera.
Genus: Zingiber
One ginger was tentatively identified in the Zingiber genus.
Data
The gingers identified were analyzed for specific characteristics that were than used to make the phylogenetic tree. Here is the data matrix, shown in the program Mesquite:
The data matrix was then exported and utilized by the program PHYLIP to create an unrooted consensus tree using maximum parsimony (from the creation of 99 most parsimonious trees) seen below:
Discussion
As noted above, the consensus tree created is unrooted, thus it is not possible to make inferences about the placement of the root. But looking at the nodes further up the tree, it is possible to speculate on relationships between specific individuals. The tree was also imported back into Mesquite in order to trace character traits. The strongest relationship seen is between Alpinia havilandii (Indiv22) and Taxon_Ginger10 (Indiv35). The nodal support value is 1.00, meaning this relationship occurred in all trees created. This is rather interesting because an individual in an unknown genus seems more closely related to the Alpinia havilandii than the other individual in the Alpinia genus (Indiv25). This could be because there are more floral characteristics available for Taxon_Ginger10 (Indiv35) than for the other Alpinia species (Indiv25). These floral characteristics may make Indiv35 appear more related to Alpinia havilandii. As seen below, when the characters were traced in Mesquite, it appears that inflorescence placement was a connecting factor between these two individuals.
Another strong relationship is seen between Costus speciosa (Indiv19) and Plagiostachys albiflora (Indiv26) with a nodal support value of 0.80. In this case, the partitioning occurred in 80% of the created trees. This is unexpected given the fact that the inflorescences occur in two separate places on these plants, but perhaps the other characters are more similar between the two individuals and overcome this seemingly large difference. Characters are also unweighted in this tree, thus all characters are treated as equally important. Tracing characters in Mesquite revealed many similar character traits between these individuals, such as hair presence.
The final branch partition with a decent amount of nodal support (0.70) is the branch which splits individuals 35 and 22 from individuals 27, 24, 7, 37, 19, and 26. This is a wide split encompassing many different individuals, so it is difficult to pinpoint possible characteristics related to such a division. However, one factor that may have contributed to the support of the node close is leaf edge appearance.
Beyond these few inferences, it is not possible to come to any broader conclusions based on this specific tree. The individual gingers discovered are from multiple genera and display quite diverse characteristics that have lead to many instances of low nodal support values in the final consensus tree. The tree has, however, suggested an interesting relationship for one of the unknown individuals (Indiv35), thus it has provided perhaps a slight inclination as to which genera this one individual may belong (Alpinia?).
References
- ↑ Larsen, K. Ibrahim, H. Khaw, S.H. and Saw, L.G. Gingers of Peninsular Malaysia and Singapore Malaysia: Natural History Publications (Borneo) Sdn. Bhd. 1999.
My Focal taxa
Individual | Determined by | Date | Taxon | Genus | Species | Morphotype |
---|---|---|---|---|---|---|
Indiv19 | Kimberly | 18 June 2010 | Taxon_Ginger4 | |||
Indiv19 | Kimberly | 2 July 2010 | Costus speciosa | Costus | speciosa | |
Indiv21 | Kimberly | 25 June 2010 | Taxon_Ginger5 | |||
Indiv21 | Kimberly | 29 June 2010 | Etlingera muluensis | Etlingera | muluensis | |
Indiv22 | Kimberly | 25 June 2010 | Taxon_Ginger6 | |||
Indiv22 | Kimberly | 29 June 2010 | Alpinia havilandii | Alpinia | havilandii | |
Indiv24 | Kimberly | 29 June 2010 | Etlingera | Etlingera | ||
Indiv24 | Kimberly | 29 June 2010 | Taxon_Ginger7 | |||
Indiv25 | Kimberly | 29 June 2010 | Alpinia | Alpinia | Taxon_Ginger8 | |
Indiv26 | Kimberly | 29 June 2010 | Plagiostachys albiflora | Plagiostachys | albiflora | |
Indiv27 | Kimberly | 29 June 2010 | Zingiber | Zingiber | ||
Indiv27 | Kimberly | 29 June 2010 | Taxon_Ginger9 | |||
Indiv3 | Kimberly | 8 June 2010 | Taxon_Ginger1 | |||
Indiv35 | Kimberly | 1 July 2010 | Taxon_Ginger10 | |||
Indiv37 | Kimberly | 2 July 2010 | Taxon_Ginger11 | |||
Indiv7 | Kimberly | 10 June 2010 | Taxon Ginger2 | |||
Indiv8 | Kimberly | 10 June 2010 | Taxon Ginger3 |