Page:Manual of the New Zealand Flora.djvu/718

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678
ORCHIDEÆ.
[Pterostylis.

Lip attached by a short claw to the basal projection of the column, mobile; lamina linear or oblong, produced at the base above the claw into a long or short usually curved appendage. Column elongated, incurved, furnished on each side of the rostellum with a quadrangular or hatchet-shaped membranous wing, the base produced into a horizontal projection. Stigma on the face of the column below the wings, oblong. Anther terminal, erect, 2-celled; pollinia 4, granular, free.

{{smaller block|About 40 species are known. Of the 11 found in New Zealand, 2 are common Australian plants, the others are endemic. The remainder of the genus is Australian, with the exception of one species in New Caledonia. The mode of fertilisation is most curious, and is well worth an attentive study. The upper sepal and petals connive, and form a hood, at the back of which the column is situated. The irritable lip hangs out of the entrance to the flower, and forms a convenient landing-place for insects. When touched by an insect it springs up, carrying the insect with it, and imprisoning it within the flower. The insect can only escape by crawling up the column and passing between the two membranous projecting wings, emerging directly in front of the anther. In doing this, it is first smeared with viscid matter from the projecting rostellum, and then drags away the pollinia, which can hardly fail to adhere to its sticky body. When visiting another flower, it must pass over the stigma before escaping, and is almost certain to leave some of the pollinia on its viscid surface. For a fuller account, see a paper by myself in Trans. N.Z. Inst. v. 352.

A. Antennæa. Lower lip erect, its lobes narroived into long points embracing the galea.
* No broad radical leaves. Cauline leaves linear, grass-like, sheathing the whole stem.
Tall, 6–18 in. Leaves ¼–½ in. broad. Flower large, 2–3 in. long; sepals and petals produced into long filiform points 1. P. Banksii.
Short, stout, 4–10 in. Leaves ½–¾ in. broad. Flower small, ¼–¾ in. long; sepals and petals with short subulate points 2. P. australis.
Slender, 4–10 in. Leaves ⅛–¼ in. broad. Flower small, ¼–¾ in. long; sepals and petals with short subulate points 3. P. graminea.
** Radical leaves broad, oblong to ovate or orbicular, few or numerous and rosulate. Cauline leaves narrow, often reduced to sheathing bracts.
Slender, 4–12 in. Lower leaves ½–1½ in., oblong; cauline 2–5, lanceolate, flat. Flower ¾–1½ in.; galea not decurved 4. P. micromega.
Stout or slender, 6–12 in. Lower leaves large, 1½–3½ in., broadly oblong; cauline few, large, flat. Flower 1–1½ in., galea much decurved at the tip 5. P. Oliveri.
Stout, glabrous, 2–8 in. Lower leaves subrosulate, 1–1¾ in., elliptic-oblong; cauline of 1 or 2 sheathing bracts. Flower ¾ in.; galea arched but not decurved 6. P. foliata.
Small. 2–3 in. Lower leaves 2 or 3, large, ¾–2 in., broadly oblong; cauline wanting. Flower ½–¾ in. 7. P. venosa.
Slender, glabrous, 2–8 in. Lower leaves long-petioled; blade ¼–⅓ in., ovate; cauline narrow, flat. Flower ½–1 in. 8. P. trullifolia.
Puberulous, 2–6 in. Lower leaves short-petioled; blade small, ovate; cauline of 2–4 sheathing bracts. Flowers ⅓–½ in. 9. P. puberula.