Rosaceae (Rose family)

 

  1. Annuals, perennial herbs, shrubs, or small trees.
  2. Leaves – alternate, opposite in Coleogyne, simple or compound, often armed with prickles, usually with stipules, often borne in clusters of short side branchlets (spurs) in shrubs.
  3. Flowers – mostly complete (incomplete in Coleogyne), perfect, actinomorphic; perianth and stamens attached to the rim of a floral tube (hypanthium).
    1. Calyx – 5 fused sepals
    2. Corolla – 5 free petals (absent in Coleogyne and Cercocarpus)
    3. Androecium – stamens usually numerous.
    4. Gynoecium – pistile 1-many; if one, then compound, composed of 2-5 carpels; if several or many, then simple and free, each representing a single carpel. Ovary superior or inferior.
  4. Fruit – various types: achenes, drupes, follicle, pome, rose hip, aggregation of druplets.
  5. The family is amply represented in southern Nevada; its members often found at mid to high elevations, in blackbrush (Coleogyne) community and upward to the tops of our desert mountain ranges. Blackbrush forms dense stands where it occurs, generally considered a relictual and ecotonal plant, it occupies the landscape between the creosote-bursage community and the sagebrush community in many areas of Nevada.
  6. Economic plants
    1. Food: Eriobotrya (loquot), Fragaria (strawberry), Malus (apple), Prunus (almond, apricot, plum, peach, prune, nectarine), Pyrus (pear), Rubus (blackberry, raspberry).
    2. Toxic: Prunus (hydrocyanic acid in seeds)
    3. Medicinal: Prunus (laetrile from seeds), Rosa (rose hips)
    4. Perfumes: Rosa (attar of rose)

 

  1. The unifying feature of the Rose family is the actinomorphic, perfect flower with prominent cup-like hypanthium, and many exserted stamens. Shallow flowers have easily accessible nectar by a nectariferous disk, and insects collect abundant pollen.
  2. The fruit morphology is very diverse from rose hips (swollen hypanthium surrounding numerous achenes), to strawberries (enlarged fleshy receptacle covered with achenes) to blackberries (aggregate fruit with an elongate receptacle bearing numerous drupelets) to the inferior ovary of the apple’s pome, and the almond’s drupe.
  3. Whereas the Fabaceae is united by its fruit type and is very diverse in its floral morphology, the Rosaceae is united in its floral morphology and is very diverse in its fruit types.