Pandanus

Callmander, Martin W., Gallaher, Timothy, Buerki, Sven, Zich, Frank A. & Field, Ashley R., 2021, Pandanus grayorum (Pandanaceae), a new species endemic to north-eastern Queensland (Australia), Australian Systematic Botany 34, pp. 327-335 : 333

Keytonorth-eastern Queensland Pandanus species (eastern coast, north of latitude – 19 °)

1. Drupes unilocolar.............................................................. Pandanus zea

Drupes plurilocular (phalanges) ............................................................2

2. Axillary buds of aerial branches developing into plantlets ..................3

Axillary buds of aerial branches not developing into plantlets.............4

3. Pileus apex rounded to the stigmatic cluster, with narrow apical central sinuses restricted to the central stigmatic cluster; stigma on proximal face of the central cluster................................................. P. gemmifer

Pileus flat or slightly domed at apex, with deep apical sinuses forming small often truncate pyramids on the whole surface of the apex; stigma on the edge of a slightly truncate pyramid ..... P. grayorum

4. Syncarp with 20 – 45 phalanges; pileus free in the upper half ............ ......................................................................................... P. conicus

Syncarp with>60 phalanges; pileus free in the upper third or less......5

5. Prop roots massive, emerging from the stem at up to 3 m above ground; syncarp ovoid ...................................................................... P. oblatus

Prop roots absent or smaller emerging from the stem at or below 1 m above ground (rarely up to 2 m); syncarp spherical to ellipsoid.......6

6. Phalanges usually longer than wide; pileus sides smooth to sulcate; ascending rootlets on main stem absent or rare, leaf bases green to white; plants growing in coastal habitats ......................... P. tectorius

Phalanges usually as wide as, or wider than, long; pileus sides with a rib-and-groove pattern; ascending rootlets common or dense on main stem, leaf bases orange to red; plants growing in open savanna and swamps ...................................................................... 7

7. Phalanges broadly cuneate to orbicular, pileus sides with dark brown cracks; sides of each carpel smooth; plants not growing in permanent water...................................................................................... P. cookii

Phalanges cuneate; pileus sides without cracks; sides of carpel sides with several ridges; plants growing in swamps ..................... ............................................................................ P. solms-laubachii