Long Shoot-Short Shoot

Examples of Long Shoot-Short Shoot Organization

Among gymnosperms, there are four types of long shoot-short shoot organization found in living (extant) species.

deciduous needles in the genera Larix (larches; long shoot, young short shoots, and short shoots on an older branch of L. laricina and western larch, Larix occidentalis) and Pseudolarix (golden larch) (Family Pinaceae)
evergreen needles in the genus Cedrus (Family Pinaceae)
the maidenhair tree, Ginkgo biloba (Family Ginkgoaceae), which has distinctive fan-shaped (flabelliform) leaves, sometimes deeply bilobed

pines (Pinus, Family Pinaceae), which has determinate short shoots, the "fascicle" of needles, one to five photosynthetic leaves and several scale-like leaves wrapping the bases of the leaves (fascicles of five needles, e.g., Pinus flexilis, limber pine, and P. aristata, bristlecone pine); the trees are evergreen, and the short shoots abscise after two or more growing seasons

Some characteristic spiny plants of deserts and dry tropical habitats display long shoot-short shoot organization.

The areole of a cactus is a determinate short shoot, which develops immediately and directly (sylleptic development) in the axil of the leaf. Therefore, an areole is the equivalent of an axillary bud that continues to grow. The spines of a cactus are formed from the shoot apical meristem on the areole in helically alternate phyllotaxis, i.e., they are equivalent to alternately arranged leaf primordia that mature instead as hard spines, leaf spines. The areole remains viable often for many years, typically until the apical meristem forms a flower, when the living cells are used up and the areole then dies after the fruit finishes its growth.

The ocotillos (Fouquieria, Family Fouquieriaceae), a North American family occurring in deserts and dry tropical forests and scrubland of Mexico and the southernmost United States, has spreading wand-like long shoots and small leaves clustered on short shoots. The fouquieriaceous spine forms from hard cells on the lower half of the leaf petiole and midvein. Leaves are produced within a few days after a soaking rain or irrigation, and abscise when the plant experiences a mild water stress.
The didiereas (Family Didiereaceae), found only on Madagascar, are superficially very similar to the North American ocotillos (just described), but these families are not closely related, so the wand-like stems and long shoot-short shoot organization are here an example of convergent evolution. In Didiereaceae, drought-deciduous foliage leaves are produced just above the stem spine.

Some desert and dryland species of Family Euphorbiaceae have indeterminate short shoots, which form leaves year after year.

Euphorbia misera, a common low shrub of the western Sonoran Desert
Species of Jatropha, such as J. spathulata, J. cinerea (long shoots and short shoots), and J. cardiophylla long shoots in summer and leafless short shoot during winter) are species of North American deserts that have flexible long stems and knobby short shoots

Some trees of deserts and other dryland habitats are excellent examples of long shoot-short shoot organization.

elephant tree (Pachycormus discolor, Family Anacardiaceae; long shoots and short shoots) of the desert of Baja California, Mexico
members of the frankincense family (Burseraceae), including certain desert species in the Sonoran Desert of North America (e.g., Bursera microphylla; long shoot and short shoots) and deserts of Africa and Arabia (e.g., Commiphora)
microphyllous legumes may be trees or shrubs with short shoots
Oxalis gigantea (Family Oxalidaceae), a peculiar shrub of the fog desert zone in Chile
an assortment of small-leaved shrubs of deserts; in North America, e.g., Porlieria angustifolia (long shoots and short shoots), several species of Lycium, Condalia globosa, and numerous others