Taxaceae and Talk:Fujimoto–Belleau reaction: Difference between pages

Revision as of 13:16, 18 May 2004

Revision as of 04:08, 17 July 2007

Line 1:

{{chemistry|class=|importance=}}

[[de:Taxaceae]] [[da:Taks-familien (Taxaceae)]][[fr:Taxacée]] [[eo:Taksacoj]]

<table border="1" cellspacing="0" align="right" cellpading="2" style="margin-left:1em">

<tr><th align="center" bgcolor=lightgreen>'''Taxaceae, Yew family'''</th></tr>

<tr><th align="center" bgcolor=lightgreen>'''[[Scientific classification]]'''</th></tr>

<tr><td>

<table align="center">

<tr><td>[[Kingdom (biology)|Kingdom]]: </td><td>[[Plantae]]</td></tr>

<tr><td>[[Division (biology)|Division]]: </td><td>[[Pinophyta]]</td></tr>

<tr><td>[[Class (biology)|Class]]: </td><td>[[Pinopsida]]</td></tr>

<tr><td>[[Order (biology)|Order]]: </td><td>[[Pinales]]</td></tr>

<tr><td>'''[[Family (biology)|Family]]''': </td><td>'''Taxaceae'''</td></tr>

</table>

</td></tr><tr>

<th align="center" bgcolor=lightgreen>'''[[Genera]]'''</th></tr>

<tr><td>

'''Taxaceae''' ''sensu stricto''<br>

''[[Taxus]]''<br>

''[[Pseudotaxus]]''<br>

''[[Austrotaxus]]''<br>—<br>

'''[[Cephalotaxaceae]]'''<br>

''[[Torreya]]''<br>

''[[Amentotaxus]]''<br>

''[[Cephalotaxus]]''

</td></tr></table>

The '''Family Taxaceae''', commonly called the '''[[yew]] family''', includes three genera and about 7 to 10 species of [[conifer]]ous [[plant]]s, now generally included with all the other conifers in the Order '''[[Pinales]]'''. [[DNA]] analysis has shown that the yews are monophyletic with the other families in the Pinales (Chase ''et al''., 1993; Price, 2003), a conclusion supported by micromorphological studies (Anderson & Owens, 2003). Formerly they were very often treated as distinct from other conifers and placed in a separate order: the '''[[Taxales]]'''.

<div style="width: 250px; float:left; text-align: center;">[[image:English Yew close 250.jpg]]<br><small>''A fleshy aril surrounds each seed in the yew''</small></div>

These are much branched, small trees and shrubs with leaves alternate, 2-ranked, linear to lanceolate, and persistent ([[evergreen]]). The leaves have pale green or white stomatal bands on the undersides. Plants are [[dioecious]], rarely [[monoecious]], with a staminate strobilus (cone), and the ovule in a highly reduced cone with just one ovuliferous scale. As the seed matures, the ovuliferous scale develops into a fleshy '''[[aril]]''' partly enclosing the seed. The mature aril is brightly coloured, soft, juicy and sweet, and is eaten by [[bird]]s which then disperse the hard seen undamaged in their droppings.

The genera ''Torreya'' and ''Amentotaxus'', previously included in this family, are better transferred to the '''[[Cephalotaxaceae]]''', to which DNA testing shows they are more closely related. Alternatively, ''Cephalotaxus'' may be included, together with these genera, in a broader interpretation of Taxaceae as a single larger family (Price, 2003). In this sense, the Taxaceae includes six genera and about 30 species. The Cephalotaxaceae differ from the Taxaceae in having larger seeds (over 10 mm long) which are completely enclosed in a fleshy aril, compared to small seeds (under 10 mm long) only partly enclosed in a fleshy aril in the Taxaceae.

Some botanists have transferred ''Austrotaxus'' to its own family, the '''Austrotaxaceae''', suggesting it may be closer to the '''[[Podocarpaceae]]''' than to the other Taxaceae, but genetic evidence does not support this transfer.

==References==

* Anderson, E. & Owens, J. N. (2003). Analysing the reproductive biology of Taxus: should it be included in Coniferales? ''Acta Hort.'' 615: 233-234. (conclusion is 'yes')<br>

* Chase, M. W. ''et al.'' (1993). Phylogenetics of seed plants, an analysis of nucleotide sequences from the plastid gene ''rbc''L. ''Ann. Missouri Bot. Gard.'' 80: 528-580.<br>

* Price, R. A. (2003). Generic and familial relationships of the Taxaceae from ''rbc''L and ''mat''K sequence comparisons. ''Acta Hort.'' 615: 235-237.

==Links to other [[Pinales]]==

'''[[Pinaceae]] - [[Araucariaceae]] - [[Podocarpaceae]] - [[Sciadopitys|Sciadopityaceae]] - [[Cupressaceae]] - [[Cephalotaxaceae]] - Taxaceae'''