4S6 



PART III. — THE CLASSIFICATION OF PLANTS. 



preceding genera, the seeds are all borne on the placental region of the macro- 

 sporophyJl and are inverted ; in the following genera the seeds are axillary and 

 erect. Cryptomeiia has an erect fringed placental outgrowth. — Taxodium, is 

 the deciduous Cypress of North America ; its leaf-bearing twigs are thrown off 

 each year {T. distichuiu), or persist for two years (T. mexicanum) : the placental 

 outgrowth overgrows the macrosporophyll as the cone ripens. — Glyptostrobus 

 is the Chinese Water Pine ; it differs from Taxodium only in that the seed has 

 a wing. 



Fam, 4. Cupressineee: monoecious, sometimes dioecious: macrosporophylls 

 with a projecting placental outgrowth : seeds axillary, erect, often winged : 

 microspores without expansions of the exine : leaves always arranged in whorls. 

 In the sub-family ActinostrohincCy including the genera Actinostrobus, Calli- 

 tris, and Fitzroya,tLe ripe cone is woody and the constituent macrosporophylls 

 are arranged in a valvate manner. 



In the sub-family Tlmjopsidincs, including the genera Thujopsis and Thuja 

 (inch Libocedrus and Biota) the ripe cone is woody and the constituent macro- 

 sporophylls are arranged in an imbricate 

 manner. The most familiar species are 

 Thuja occidentalism the American Arbor 

 Vitse, and Thuja (Biqia) orirntalU, the 

 Chinese Arbor Vitse. 



In the sub-family Cupresshiie, includ- 

 ing the genera Cupressus and Chamsecy- 

 paris, the ripe cone is woody and con- 

 sists of 2-6 pairs of peltate macrosporo- 

 phylls coherent by their margins in a 

 valvate manner. The genus Cupressus, 

 the Cypress, has several seeds on each 

 macrosporophyll : in Chanifficyparis each 

 macrosporophyll bears only two seeds. 



The sub-family Junipennce, including 

 the single genus Juniperus, is distin- 

 guished from the preceding sub-families 

 in that the flowers are, as a rule, dioe- 

 cious ; the ripe cone is somewhat fleshy, 

 resembling a berry or a drupe ; it usually 

 consists of one whorl of macrosporophylls 

 each bearing one or two wingless seeds. 

 The section Caryocedrus (Arceuthos), containing the single species Juuiperus 

 drupacea, has a cone consisting of 3 or 4 whorls of macrosporopbylls ; whereas 

 in the section Oxycedrus (including Juniperus conimmiis, the Juniper; J. Oxy- 

 cedrus, J. macrocarpa, and other species), the cone consists of 1-2 wborla ; and 

 in the section Sabina (including/. Sabina, J. virginiana, etc.), it consists of 2-3 

 ^\horls ; the innermost or uppermost whorl alone is fertile as a rule, in Caryo- 

 cedrus and in Oxycedrus, but is sterile in Sabina : in Caryocedrus the (2-3) seeds 

 are coherent, in the other two sections they are free : in Sabina the flowers 

 are generally monoecious ; in Sabina also the leaves (including sporophylls) are 

 usually in whorls of 2, whilst in the other two sections they are in whorls of 3. 



Fig. 306.— 4 Branch of Thuja occi- 

 dentalis (x6) showing lieterophylly ; fc 

 flank-leaves ; / surface-leaves; Ji resin- 

 receptacle (see p. 464). B Fruit of Biota 

 orientalis (nat. size) : / macrosporophylls 

 with ventral outgrowths d.; d (in the 

 middle line) sterile sporophylls. 



