UVAL-EEAVED MILKWEED 

 Asclepias ovatifolia Dec. 



MILKWEED FAMILY 



A flower of such marked individuality as the milkweed, once 

 seen in life or in picture, is easily recognized thereafter. For 

 although several species occur in Western Canada, differing in 

 color and in many details, the unique flower-form common to 

 all, sots them apart from other plants. 



The Oval-leaved Milkweed is probably the commonest western 

 species, growing in rich, well-drained soil, either in full sunshine 

 or among bushes, from Manitoba to Alberta. Its stalks are 

 from six to eighteen inches high, its leaves, especially on the 

 underside, are soft-downy, and its greenish-white flowers, some- 

 times tinted with purple, are borne in soft umbelled clusters. 



And now to a closer study of these prettily and curiously 

 formed flowers. In addition to the calyx, and a corolla with five 

 reflexed lobes, there is in the centre of the flower a five-lobed 

 structure happily named the crown. But when the botanist speaks 

 of each lobe of the crown as a hood, and the hood as bearing a 

 horn, and the horn as having a tooth on either side, it begins to 

 grow confusing. Still, these features may be seen fairly well in 

 our picture. But to study the inner structure of the flower in de- 

 tail is impossible here. Suffice it to say that the pollen is produced 

 in minute paired masses, each pair connected by a kind of clip, 

 having a catch in the centre, and that the two pistils are em- 

 bedded in a fleshy column. The problem of the plant is to bring 

 the pollen masses of one flower into contact with the stigmas of 

 another flower, and this can only be done by insect agency. 

 Accordingly, the flowers secrete nector, and then advertise it 

 by a heavy sweet odor which attracts bees and butterflies in 

 large numbers. 



Alighting upon one of the yielding flower clusters, the heavy 

 bumble bee finds himself suddenly swinging head downward. 

 ( i rasping frantically for a foothold, his legs are likely to slip 

 into the catches on the pollen clips, and as he jerks himself free 

 the pollen is torn from the flower and remains attached to his 

 legs. Later, the same kind of a scramble for foothold while sip- 

 ping nectar results in some of the pollen being rubbed off upon 

 the stigmas of other flowers. 



To the human observer this may seem a rough way of per- 

 forming a delicate operation. It may also seem to be a highly 

 complicated mechanism for producing tlo apparently small 

 n'siilts attained, for of the thirty of forty flowers in a cluster. 

 usually only one or two become fruitful and develop into big, 

 soft pods of silky-tufted seeds. But although we may wonder 

 at Nature's methods, they are here amply justified in the final 

 result, for the milkweeds are a numerous, vigorous, widely 

 distributed, highly successful tribe of plants. 



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