July 13, 1911. 



The Weekly Florists^ Review^ 



IS 



EVOLUTION AND POLLINATION. 



[A paper by A. C. Beal, of Cornell University, 

 Itbnca, N. Y., read at the Philadelphia conven- 

 tion of the National Sweet Pea Society of 

 America, June 29 and 30, 1911.] 



During the first 100 years of the 

 history of the sweet pea only three 

 varieties or colors were known; name- 

 ly, purple with blue wings, pale red 

 with white wings (Fainted Lady), and 

 white. The black and scarlet appeared 

 in the last years of the eighteenth cen- 

 tury. It is quite probable that the 

 scarlet was far from what we conceive 

 a scarlet sweet pea should be today. 

 In Martyn's edition of Miller's Gar- 

 deners' Dictionary, 1807, we find the 

 white, the Old Painted Lady, the New 

 Painted Lady, the latter with a rose- 

 colored standard and pale rose wings. 

 Old Purple, and a variety having a 

 violet keel and wings and purple stand- 

 ard. Sayers describes the scarlet sweet 

 pea as Lathyrus flore rosea, while the 

 Painted Lady is described as ' ' fleshed ' ' 

 color. From this we may conclude 

 that the New Painted Lady, a rose- 

 colored variety, was sometimes called 

 scarlet. 



Improvement in Color. 



The first of the striped varieties was 

 offered in 1837 and since that date this 

 group has been augmented until the 

 classification now includes striped and 

 flaked (red and rose, purple and blue). 

 This classification, however, does not 

 express the real range of color in this 

 group, for we have crimson stripes — 

 for instance, America; red and rose 

 stripes on white — Aurora; red and rose 

 stripes on primrose — Jessie Cuthbert- 

 son; mauve stripes — Gaiety; blue 

 stripes — Prince Olaf and Hester; ma- 

 roon-flaked, like Senator. The Amer- 

 ican growers have introduced the ma- 

 jority of the best varieties of this 

 group, among which are America, Au- 

 rora, Columbia, Daybreak, Gray Friar, 

 Juanita, Pink Friar, Ilamona and Wa- 

 wona. Many of these are now pro- 

 curable in the waved form. 



The Blues and Pinks. 



The variety Blue Edged, the probable 

 forerunner of the picotee forms, ap- 

 peared in 1860. This was a white va- 

 riety with a well-defined blue edge, a 

 probable hybrid between L. Magella- 

 nicus and a white variety of L. odora- 

 tus. The variety, at all events, was 

 the first to exhibit a distinct blue color 

 among sweet peas. Later it was known 

 as Blue Hybrid, under which name it 

 won an award from the Eoyal Horti- 

 cultural Society. Sutton & Son ' sent 

 out Butterfly in 1878, which somewhat 

 resembled Blue Edged. The so-called 

 blues that followed were Invincible 

 Blue, Madame Carnot or Imperial 

 Bliie, 'and Captain of the Blues, all of 

 which had considerable red in the 

 standard. It was not until 1899 that 



a good blue, in Navy Blue (Lord Nel- 

 son), appeared. 



The first of the soft pink varieties 

 was Crown Princess of Prussia, 1868-9. 

 Isa Eckford, Peach Blossom and Lovely 

 are the improved varieties of this color. 



Improvement in Form. 



The efforts of the breeders of sweet 

 peas have not all been directed toward 

 the development of new shades of 

 color. The form of the flower has also 

 received attention. The earliest repre- 

 sentations of sweet pea flowers show a 

 loose, irregular bloom, with the edges 

 of the standard turned back; that is, 

 reflexed. Otten, if not always, the 

 standard had the notch in the apex 

 and frequently in the margin. The 

 standard, which is the principal part 

 of the flower, has been improved in sub- 

 stance and the notches have been elim- 

 inated. The old type had a narrow 

 base, and with the improvement noted 

 has come a filling out of the lower 

 edges of the standard so that the out- 

 line approaches a circle. 



In their efforts to secure varieties 

 of the best expanded or open form, 

 many beautiful hooded varieties were 

 originated. While this form was con- 

 demned as inartistic by many sweet 

 pea specialists, it nevertheless secured 

 a permanent place. Prima Donna, 

 Lovely and Countess of Badnor are of 

 this form. 



The Spencer Type. 



When many had reached the conclu- 

 sion that no further advances in either 

 size or form were to be expected and 

 that the efforts of future breeders 

 would be directed toward securing new 

 colors and more flowers per stem, Na- 

 ture demonstrated that she had other 

 surprises in store. 



In 1901 the Countess Spencer variety 

 was exhibited and caused quite a sen- 

 sation. The National Sweet Pea So- 

 ciety awarded it the highest honors. 

 This variety was distinct from all pre- 

 ceding introductions, because the stand- 

 ard and wings waved. The flowers 

 were large, and borne in fours on 

 stout stems. It was introduced in 1904. 



The parentage of this variety has 

 been given as (Lovely x Triumph, 

 1898) X Prima Donna, 1899. However, 

 there appeared in 1905 a variety named 

 Gladys Unwin, which was the same 

 color, but smaller and less waved than 

 Countess Spencer, and which was a se- 

 lection from Prima Donna without 

 knorwn crossing being effected. These 

 varieties, however, were forerunners of 

 the new type which revolutionized 

 sweet pea culture in England and has 

 revived and quickened the interest in 

 America. 



Pollination. 



We have previously noted that the 



pistil and stamens are enclosed in the 

 keel formed by the partial coalescing 

 of the two lower petals. A slight pres- 

 sure upon the base of the keel will 

 cause the pistil to appear suddenly in 

 the tip of the keel. The stigmatic sur- 

 face is usually covered with pollen, 

 and at the same time the stamens ap- 

 pear to view. If the pressure is re- 

 leased, these organs disappear as sud- 

 denly from view. 



Process of Self -Fertilization. 



Those who are looking for flower 

 adaptations for the promotion of cross- 

 fertilization would say at once that 

 here we have a mechanism which is 

 operated by the weight of a bee alight- 

 ing on the keel, and the pistil and 

 stamens rise up, striking it upon the 

 body, receiving and giving pollen. 

 Thus, as the insect visits flower after 

 flower, natural cross-fertilization is car- 

 ried on. 



This, however, is not the case. In 

 the first place, if we examine flowers 

 in the bud stage, we find the pollen 

 ripe. The position and condition of 

 the stigma changes, for before the ma- 

 turation of the pollen the stigma is be- 

 low the anthers. A day or two later 

 the stigma has risen to a position 

 among the anthers and is viscid enough 

 to hold the pollen grains. 



In another day or two it has grown 

 beyond the anthers. Self-fertilization 

 has taken place and the development 

 of the legume begun. This process has 

 taken place before the flower is fully 

 open. Some time later the pistil is 

 pushed out of the protecting keel by 

 the developing pod. 



Not Dependent on the Bees. 



Such is the normal fertilization of 

 sweet peas, as observed upon examina- 

 tion of the flowers. Attention has been 

 called to the fact that the sweet pea 

 stood practically still for 150 years, 

 and the question is asked how this can 

 be reconciled with natural cross-fer- 

 tilization. 



During the writer's experience in 

 the field last season for three months, 

 studying varieties and recording ob- 

 servations, not a single instance oc- 

 curred of a bee alighting upon the keel 

 of the flower, nor were any observed 

 crawling between the wings. AH- the 

 bees observed visiting the flowers 

 alighted on the outside of the wings, 

 and in practically every case thrust 

 the proboscis down between the right 

 wing and the standard. In this con- 

 nection it may be mentioned that the 

 bees did not show a preference for any 

 particular color, but flew from row to 

 row and from color-section to color- 

 section. 



T. H. Dipnall has observed that bees 

 attack sweet pea flowers. The bee, a 

 yellow and white banded species, 

 alighted on the calyx, crawled around 

 to a certain position, and cut a hole 

 through the calyx so that it could 

 thrust its proboscis through and suck 

 the nectar at the base of the pod. The 

 reason is not clear why the insect pre- 

 fers one side of the flower, since the 

 structure is similar on each side. 



It is, to be remembered in this dis- 

 cussion that sweet peas grown under 

 glass in winter are not visited by bees, 

 but every flower in sunny weather will 

 set seed if the blooms are not kept 

 cut. 



[Oonclnded on page 68.] 



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