908 PATAGONIAN EXPEDITIONS: BOTANY. 



components, and end with the most complex. There are some irreducible 

 cases of families whose natural affinities are unknown, as Euphorbiaceae, 

 and Polygalaceae. 



The Patagonian region contains representatives of about 113 natural 

 families, of which the Dicotyledones have 92, and the Monocotyledones 

 about 17 families, whilst there are 4 families of Gymnosperms. 



THE ORDERS AND FAMILIES. 



Subkingdom SPERMATOPHYTA = Phanerogamia, or Flowering-plants (Embryophyta sipho- 



nogama Engler), having pollen and producing seeds with embryo. 



A. Superclass GYMNOSPERMIA (families 1-4), pp. 140-145. Trees or shrubs with diclin- 

 ous flowers, the carpels not forming a closed ovary nor bearing a stigma. 

 b. Branching freely ; the wood consisting of tracheids, without ducts (saving resiniferous ducts), 

 forming annual rings and bark. Flowers mostly in staminate and pistillate cones, with- 

 out perianth. (CONIFERS, p. 140.) 

 c. Leaves in spirals. Cones many-carpellary, dry. Seed I in each carpel, inverted. 



Family I. Araucaria of Pinacece, p. 140. 



c2. Leaves in whorls of 2-4. Cones woody or fleshy, few- (1-4)- carpeled. Seeds often 

 several in each carpel, erect. Stamens with 3-5 pollen sacs, the pollen wingless. 



Family 2. Cupressaceee, p. 141. 



^3. Leaves acicular or broader, rarely opposite. Cones often fleshy, few-carpeled, carpels 

 I -seeded. Stamens with 2 pollen sacs, the pollen winged. 



Family 3. Podocarpece of Taxacece, p. 142. 



l>2. Branching or with simple stem ; jointed and with ducts in the wood. Leaves reduced to 

 scales. Flowers with a small perianth. Seeds fleshy, grape-like. (GNETALES.) 



Family 4. Ephedracca, p. 144. 



AA. Superclass ANGIOSPERMIA. Trees, shrubs or herbs, having fibrovascular bundles ; 



the flowers varying as to sexuality and perianth ; the carpels forming a normally closed, 



stigmatiferous ovary. 1 Families 5-113, p. 146-906. 



B. Class MONOCOTYLEDONES or Endogens. Having stem endogenous ; leaves usually 



parallel-veined, non-stipulate ; flowers normally 3-merous ; embryo with i cotyledon. 



Families 5-21, pp. 146-324. 

 C. (Acyclicce.) Flowers with the parts spirally arranged, showing little structural 



symmetry. 

 d. Perianth none, or consisting of bristles or scales. 



e. (Pandanales.) Perianth of hypogynous bristles. Stamens i-oo ; carpels i-oo, 



1 Terms explained: Acrandroits, having staminate flowers uppermost ; acrogynous, having pistil- 

 late flowers uppermost ; eudiplostemonous, having the outer stamens antisepalous ; obdiplostemonous, 

 having the outer stamens antipetalous. Tepaliferom families are such as have double perianth 

 of tepals, not differentiated into petals and sepals, but all similar. The tepals may be colored or 

 green or dry scales like chaff. Sepalo-petalous flowers have a double perianth consisting of 

 differentiated sepals and petals. 



