Phyllocladus
Content
Description
Small to large trees up to 30 m tall, with smooth, dark, platy bark which is reddish or yellowish and fibrous within.
Seeds are oval and wider than thick, protrude from the bright red ripe cone, have a crooked micropyle at the tip, and are dark brown to black.
Distribution
Australasia: Tasmania (Tasmania present), New Zealand present, highlands of Malesia present
Five closely related species, three in New Zealand, one in Tasmania, and one in the highlands of Malesia. .
Notes
The unique cladodes and fewer chromosomes set Phyllocladus apart from other Podocarpaceae but, as SINGH () points out, they share such common features as winged pollen with a prothallial tissue, an epimatium, and binucleate embryo cells. Other significant common traits are a solitary ovule per fertile bract, two pollen sacs per microsporophyll, and fused pairs of cotyledons as well as fleshiness of the mature cone and a mature seed of essentially identical form as those of other genera with naked seeds in the family. The erect seed with an aril has suggested a transitional position towards Taxa-ceae but the ovule is not terminal as in this group and the aril is not fleshy. FLORIN regarded the later developing aril as having nothing to do with the epimatium () but this position requires the loss of any epimatium-type structure and the subsequent development of the morphologically similar (asymmetrical) aril in the corresponding location. In fact the erect position of the ovule may tend to suppress or delay the development of the epimatium which elsewhere arches over and around the base of inverted ovules. The only other genus of the family with an erect ovule has no epimatium at all while that of Phyllocladus, though eventually well developed, is retarded, appearing only after fertilization. The genus is a comfortable member of the Podocarpaceae and a distinct family, as KENG () proposed, does not seem justified. The intriguing thesis of KENG () that the cladodes probably represent a relic of ancient progymnosperm telomic branch systems seems hardly sustainable in the light of the above as well as the further fact that perfectly typical coniferous leaves are produced in the juvenile phase.
Citation
MIRBEL 1978: 249, 43. – In: J. Arn. Arb.: fig., 4 maps
DE LAUB. 1969 – In: J. Arn. Arb.: 277
MIRBEL 1916 – In: Bot. Jahrb.: 33
PILGER 1903: p. 94. – In: Pfl. R.: f. 18
VAN ROYEN 1979 – In: Alpine Fl. New Guinea: 8
MIRBEL 1975 – In: Taxon: 289
MIRBEL 1963 – In: Gard. Bull. Sing.: 123, 127
MIRBEL 1977 – In: Pl. Syst. Ecol.: 235
MIRBEL 1926 – In: E. & P., Nat. Pfl. Fam., ed. 2, 13: 249
GAUSSEN 1974: p. 13. – In: Gymn. Act. & Foss.: f. 675-9, map (f. 679bis)
L.C. RICH. 1874 – In: Ann. Sci. Nat.: 37
L.C.&A. RICH. 1826: Comm. Bot. Conif. &Cycad: 129: t. 3, f. 12
KENG 1962: p. 69. – In: Ann. Bot. n.s.: 14 fig.
MIRBEL 1974 – In: Ann. Bot.: 757