308 FIELD AND WOODLAND PLANTS 



but usually only one produces pollen, and this one commonly consists 

 of one or two club-shaped masses. The ovary is inferior, often 

 twisted so as to invert the flower, and sometimes so long as to 

 be mistaken for a flower stalk. The stigma is hollow, sticky, and 

 situated just in front of the column above mentioned. The fruit 

 is a three-valved capsule, containing many seeds. 



Orchids are generally scented flowers, and produce nectar which 

 is stored either in the cavity of the spur, or within the tissue of the 

 same. In the latter case it cannot be obtained by insects unless 

 they bore into the substance of the spur, and the delay caused 

 renders the removal of the pollen more certain. While the nectar 

 is being withdrawn, the head of the insect is pressed against a 

 sticky disc at the base of the pollen masses, with the result that 

 both disc and pollen masses are bodily removed, and the insect 

 leaves the flower with the whole attached to its head. It often 

 happens, too, that the pollen masses bend forward as the insect 

 flies through the air, and thus they are more likely to be pressed 

 against the stigma when another flower is visited. Here, then, is 

 another wonderful contrivance for the purpose of securing cross- 

 fertihsation, and the whole process may be imitated by thrusting 

 the point of a pencil into the spur of a flower which has not been 

 previously visited by an insect, and then inserting the point into 

 the spur of a second flower. It should be noted, also, that the 

 pollen is not all removed by contact wdth the sticky surface of a 

 stigma against which the pollen masses are pressed, and thus the 

 pollen obtained from one flower will often fertilise several others. 



Om- first species — the Broad-leaved Helleborine {Epipactis 

 latifolia), is common in hilly woods, where it flo\s'ers during 

 July and August. Its single stem grows from one to three feet 

 high, and the leaves are broadly ovate and ribbed. The flowers 

 are greenish, with reddish-purple hps, and are arranged in a long, 

 loose, one-sided raceme. The sepals are ovate, longer than the acute 

 lower lobe of the lip ; and the bracts are generally longer than the 

 flowers. The ovary is downy, and not so long as the bracts, 

 (Plate II, Fig. 5.) 



The somewhat similar Large White Helleborine (Cephalanthera 

 grandiflora), which bears creamy white flowers in May and June, 

 is also common in some of the woods on calcareous soils. 



The Pyramidal Orchis (0. pyramidalis) grows in limestone 

 pastures, flowering during July and August. This species varies 

 from six to eighteen inches in height, and has linear, acute leaves. 



