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Prince Albert yew, Lindley 1851

Saxegothaea - Prince Albert yew description


Evergreen trees with a dense crown composed of closely spaced branches extending almost to the ground, commonly hiding the single, straight trunk, which may become relatively massive for the height. Bark obscurely fibrous, peeling in irregular patches. Branchlets all elongate, without distinction into short and long shoots, hairless, turning brown after the first year, distinctly grooved between the attached leaf bases. Resting buds poorly differentiated, consisting solely of as yet unexpanded normal foliage leaves. Leaves spirally attached but partially rearranged into two ragged rows extending out to the sides of the twig by bending of the petioles, needlelike and resembling those of yews (Taxus), straight or slightly sickle-shaped, flattened top to bottom.

Plants monoecious. Pollen cones single or spirally arranged in groups of up to about 16 at the end of an otherwise unmodified shoot, each at the end of a short bare stalk and solitary or in pairs in the axil of an ordinary or slightly reduced foliage leaf. individual pollen cones cylindrical, with a few scalelike bracts at the base and with numerous, spirally arranged triangular pollen scales, each bearing two pollen sacs. Pollen grains large (50-75 µm in diameter), roughly spherical, without air bladders, very smooth, and with a slightly protruding germination point. Seed cones single on a short scaly stalk at the tip of an otherwise ordinary branchlet, fully condensed, consisting of closely spirally arranged bracts intimately united with the somewhat fleshy seed scales, each scale with a single ovule embedded near the base with its opening pointing down into the cone axis. Seed scales becoming partially united with one another near the bases at maturity. Seeds skirted by a thin, fleshy aril, unwinged, maturing in a single season. Cotyledons two each with two veins. Chromosome base number x = 12.

Wood soft and light, with little differentiation between sapand heartwood, both light brown to yellowish brown, sometimes with darker streaks or even a reddish brown false heartwood due to bacterial or fungal staining. Grain moderately fine and even, with inconspicuous growth rings marked by a few rows of small but thin-walled latewood cells. resin canals absent but with scattered individual resin cells.  

Leaves without stomates above and with 8-12 somewhat irregular lines of stomates forming a broad, pale stomatal band on either side of the midrib beneath. Each stomate sunken beneath and largely hidden by the four to six surrounding subsidiary cells, which rise in a steep, narrow, lobed, and discontinuous Florin ring. Midvein single, prominently raised above and beneath, with one small resin canal immediately beneath it and with wings of transfusion tissue extending out to the sides. Photosynthetic tissue covering the upper side of the leaf.

One species in the Andes of southern South America. Many features of Saxegothaea (named for Queen Victoria’s husband Prince Albert of Saxe-Coburg-Gotha, who lived 1818 - 1861), including chromosome structures, wood anatomy, and embryo development as well as DNA studies, clearly ally it with the Podocarpaceae. Nonetheless, its compact, ordinary looking seed cones and pollen grains without even a hint of air bladders are very unlike the conditions found in Podocarpus and most other Podocarpaceae, so its exact relationships to other genera in the family are uncertain. John Lindley, who originally described and named the genus in 1851, thought it provided a link between Podocarpus and more typical conifers, in essence suggesting that it was what used to be referred to as primitive within the family. In fact, this idea is generally corroborated by DNA studies, which are consistent with a very early divergence of the ancestors of Saxegothaea within the lineage that led to the group of genera that includes. Podocarpus and Dacrydium, one of two main lineages within the family. There is no consensus on which of these patterns (if either) reflects the true relative position of Saxegothaea and its ancestors. In any event, the other genera with relatively compact, multiscaled seed cones, Acmopyle, Microcachrys, and Phyllocladus, also seem to have diverged relatively basally, so the highly reduced seed cones typical of Podocarpus and most other genera do not appear to be the ancestral condition within the family. Unlike for many other podocarp genera, there is no accepted fossil record for the genus that might help shed light on the timing of these events and hence on the likelihood of one or another evolutionary branching scheme. While Saxegothaea conspicua has been cultivated for more than 150 years, it is uncommon in cultivation, and no cultivar selection has taken place.




Attribution from: Conifers Garden