Nature and development of plants . ated that betterresults follow when crossing is effected between sporophylls ofthe same length, i. e., long with long, short with short, arose in many of the orders, as among some of theknotweeds, buttercups and rose families and in the gentians,primroses, forget-me-not, etc. A higher and more characteristic type of the order is seen inthe Oenothera and in the great willow-herb (Chamaenerion, Fig. DEVELOPMENT OF PLANTS 43i 323). This latter plant flourishes in rather dry soils, forminglarge colonies by its underground stems and gaining in con-
Nature and development of plants . ated that betterresults follow when crossing is effected between sporophylls ofthe same length, i. e., long with long, short with short, arose in many of the orders, as among some of theknotweeds, buttercups and rose families and in the gentians,primroses, forget-me-not, etc. A higher and more characteristic type of the order is seen inthe Oenothera and in the great willow-herb (Chamaenerion, Fig. DEVELOPMENT OF PLANTS 43i 323). This latter plant flourishes in rather dry soils, forminglarge colonies by its underground stems and gaining in con-spicuousness through its terminal racemes of large deep purpleflowers. The parts of the flower are in fours. The receptacleadheres to the ovary and bears the linear segments of the calyxalternating with the round spreading petals. At the time of theopening of the flower the eight anthers are shedding their sporesand in line with the nectaries, while the four-lobed stigma isclosed and bent backward (Fig. 323, C, s). A day later the. Fig. 323. Higher forms of the Myrtales, flowers epigynous: A, flowerof Oenothera—0, ovary. B, enlarged sectional view of flower, showingthe receptacle enveloping the ovules. The sepals cohere, forming a tube,t, that bears at its summit the petals, />, and stamens; c, lobes of the , inflorescence of the great willow herb (Chamaenerion)—s, closedstigma in young flowers; 0, opened stigmas in older flowers; a, stigmatouching anthers in withered flowers. D, capsule opening and dischargingthe seeds. E, a seed enlarged.—C after Kerner. stigmas assume the position shown in the lower flowers, the lobescurving backward so as to lie in the pathway leading to thenectaries (Fig. 323, C, 0). It is evident that these positionsmust necessitate a crossing if the flowers receive the proper vis- 432 THE UM BELL ALES itors. If, for any reason, crossing should fail autogamy results,owing to the continued curvature of the stigmas, which are finallybrought
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