Page 4 - Bulletin of the Cupressuss Conservation Project vol04_nr1 2015

species (DALLIMORE & JACKSON 1966; DEL FUEYO 1996; ECKENWALDER 2009; FARJON 2010).
A line drawing in DE LAUBENFELS (1972) is one of the rare illustrations of the pollen cones of
Podocarpus gnidioides that exist. A 10-years-old male individual cultivated as a potted plant and
overwintered in a temperate house in the private living collection of HUBERTUS NIMSCH,
Bollschweil, St. Ulrich (Germany), started forming pollen cones for the first time in spring 2014.
This was taken as an opportunity to investigate the morphology and anatomy of pollen cones and
pollen of Podocarpus gnidioides in detail.

2 Material & Methods

2.1 Material

21 pollen cones were collected on 5.5.2014 shortly before anthesis. As typical for conifers the
pollen cone development is simultaneous within an individual and all material that was available
has been collected in a more or less the same late ontogenetic stage. Thus, ontogenetic studies about
the pollen cone development could not be done.

2.2 Methods

Freshly collected material was photographed and then fixed in FAA (100 ml FAA = 90 ml 70%
ethanol + 5 ml acetic acid 96% + 5 ml formaldehyde solution 37%) before being stored in 70%
ethanol. The cone-anatomy was studied from serial sections using the classical paraffin technique
and subsequent astrablue/safranin staining (GERLACH 1984). For SEM-analysis the FAA-material
was dehydrated in formaldehyde dimethyl acetal (FDA) for at least 24 hours (GERSTBERGER &
LEINS 1978) and critical point dried. Sputter coating was done with a Sputter Coater SCD 50 Bal-
tec (BALZERS). The specimens were examined with an AURIGA ZEISS TM. Macrophotography was
accomplished using a digital camera (CANON POWERSHOT IS2) and microphotography with a
digital microscope (KEYENCE VHX 500F) equipped with a high-precision VH mounting stand with
X-Y stage and bright field illumination (KEYENCE VH-S5).

2.3 Special terms

The term “sporophyll” or “microsporophyll” is avoided for the sporangia bearing structure in
conifers. Otherwise this would introduce a priori a homology with the terminology applied. They
are termed here as “sporangiophore” or “microsporangiophore”. The small green scale developed
adaxial at the central stalk of hyposporangiate sporangiophores is called “scutellum”.

3 Results

3.1 Morphology and anatomy of pollen cones

On lateral shoots pollen cones are developed in distal parts of the last year’s growth (figs 1A, 1C,
2A). They are inserted solitary in the axial of a typical needle-leaf (figs 1A, 1C). The pollen cone is
surrounded by 13-17 small persisting bud scales (fig. 2C, 2 E). The majority of the bud scales are
small triangular, green and about 1 mm long and 1 mm wide (figs 2C, 2E ). Only the inner bud
scales can sometimes show the appearance of a typical needle-leaf (figs 1E, 1F), however they are
strongly reduced in size. Ripe cones are erect and between 10-25 mm long and 2-2.5 mm wide
(fig. 2A). The stalk is between 5-8 mm long and 1-1.5 mm in diameter (figs 2C, 2D). The cones
consist of 83-126 densely spirally set hyposporangiate microsporangiophores (fig. 2B).
Perisporangiate microsporangiophores were not found. Microsporangiophores are developed even
shortly below the apex and the apex can still be recognised as a small tip (figs 4A, 4B, 4C, 4D).
Even the most distal microsporangiophores are fertile (fig. 3D). In one of the investigated cones the
cone-axis terminates with a microsporangiophore (figs 4E, 4F). The scutellum of this terminal
microsporangiophore is quite short and roundish, peltate-like (figs 4E, 4F). The vascular bundle
strand of the cone-axis terminates blindly in the distal part of the scutellum of the terminal
microsporangiophore (figs 4E, 4F).

Bulletin CCP, vol. 4, n° 1. ─ 37 ─