Order 1. Cycadales; family Cycadaceæ. Cycas, Zamia, etc. Order 2. Gingkoales; family Gingkoaceæ. Gingko. Order 3. Pinales (or Coniferæ); family 1. Taxaceæ. Taxus, the common yew in the eastern United States, and Torreya, in the western United States, are examples. family 2. Pinaceæ. Sequoia (redwood of California), firs, spruces, pines, cedars, cypress, etc. Order 4. Gnetales. Welwitschia mirabilis, deserts of southwest Africa; Ephedra, deserts of the Mediterranean and of West Asia. Gnetum, climbers (Lianas), from tropical Asia and America. =638.= TABLE SHOWING HOMOLOGIES OF SPOROPHYTE AND GAMETOPHYTE IN THE PINE. TERMS CORRESPONDING TO THOSE USED IN PTERIDOPHYTES. COMMON TERMS. -------------+-------------------------------------------------- | Sporophyte = Pine tree. | Spore-bearing part = Male and female cones. -------------+-------------------------------------------------- Sporophyte | Microsporophyll = Stamen. | Microsporangium = Pollen sac. -------------+-------------------------------------------------- | Microspore = Pollen grain. | Mature microspore is = Mature pollen grain. | rudimentary male | prothallium with | rudimentary | antheridium | Large cell (part of = Vegetative cell | antheridium wall?) of pollen grain. | Antheridium cell = Small cell of pollen Male | grain. gametophyte | Antheridium cell divides = Generative cell. | to form stalk cell and | central cell of | antheridium | (male sexual organ) | Central cell of = Paternal cells, | antheridium or generative cells. | divides to form | two sperm cells -------------+-------------------------------------------------- | Macrosporophyll = Ovuliferous scale (cover | scale and carpellary | outgrowth); or three | carpels united into Sporophyte | ovuliferous scale, | the central one sterile | (in axil of cover scale). | Macrosporangium covered = Nucellus covered by | by integument integument = ovule.