BIOL 2242 Lecture Notes - Lecture 21: Coleus, Phyllotaxis, Galium

• School: University of Manitoba
• Department: Biological Sciences
• Course: BIOL 2242
• Professor: Isobel Waters

Document Summary

25. 20, p. 593: both have an axis bearing leaf-like structures. Branch has sam, whereas compound leaf doesn"t: presence of axillary buds (cid:523)plus stipules depending of species(cid:524) (cid:523)leaflets don"t. Reflects indeterminate status of branch versus determinate leaf. In axil of all simple leaves on a branch and at base of compound leaves but not at base of leaflet: plane of leaves. Leaflets lie in same plane; leaves (simple or compound) on a branch lie on different planes. Ecological consequences of phyllotaxy: helical pattern is most common. Smaller the angle, the more files of leaves without directly overtopping lower leaves. Selective advantage in shady habitats: very small angle in species with basal growth (form rosette) Obeys fibonacci series (watch video: distichous patter in grasses. Feasible to have many leaves overlapping in high light prairie habitats: further aided by vertical habitat. But high risk of water loss: require large structural investment.