. Plants of New Zealand. bears only a solitary flower, itis clear that cross-pollination must be effected not onlybetween different flowers, but between different plants. Theflowers of this genus are pollinated by certain species of method of entrapping insects seems to be unique inthe order. The large green hooded flowers of this genus are, inspite of their size, not very conspicuous, and it is not alwayseasy to determine what attraction they possess for the insects. The Ahsorptiun of Moisture. Orchids are not only remarkable for the structure of theflower, and for their methods of
. Plants of New Zealand. bears only a solitary flower, itis clear that cross-pollination must be effected not onlybetween different flowers, but between different plants. Theflowers of this genus are pollinated by certain species of method of entrapping insects seems to be unique inthe order. The large green hooded flowers of this genus are, inspite of their size, not very conspicuous, and it is not alwayseasy to determine what attraction they possess for the insects. The Ahsorptiun of Moisture. Orchids are not only remarkable for the structure of theflower, and for their methods of pollination, but in many otherways. Thus, they have often highly specialized methods ofabsorbing moisture. There is in New Zealand, a minutespecies of Bolbophylhmi, B. Pijgmceiim. It is not uncommon,,but is frequently overlooked, as it is so genus has received its generic name, because, at the baseof each leaflet, is a small bulb, in which are concealed the Trans. Vol. V., p. 352. THE ORCHID FAMILY 119. Fig. 32. Pterostylis Baiiksii (§ nat. size). 120 PLANTS OF NEW ZEALAND stoinata by which the plant transpires. The object of thisarrangement is two-fold. It enables free transpiration to go onin the wet season, when the plant is surrounded by moisturethat would otherwise choke the pores; and, in the dry season, theconcealment of the pores checks excessive transpiration. Again,Dendrohimn and Earina very frequently grow upon trees, or inthe clefts of rocks. In such situations, of course, no moisturecan be received from the soil; and if the leaves were thin andbroad, there would be excessive transpiration, and the plantwould wither. Consequently, they are narrowed, and havebecome rather thick and leathery. The dimensions given inHookers Handbook for the breadth of the leaves in thesegenera are : E. mucronata ^ to i in., E. suaveolens ^ in.,D. Cunninghamii J in. Contrast these leaves with those of ashade-growing plant like Corysanthes macrantha. The latterhas rou
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectplants, bookyear1906
