APETAL^. 



67 



LESSON XI. 



Sub-Class II. Exoqens. Dicotyledons. 



{1. Apetalse, no petals. 

 2. Monopetalie, one-petalled. 

 3. Polj/petalx, many-petalled. 



92, 93. Apetalse, Ovary Adherent : Mistletoe. 94. Oaks. 95. Wal- 

 nuts. 96. Eafflesia. 97. Ovary Free : Catkin-bearers. 98. Nettle to 

 Amaranth. 99-103. Monopetalie, Ovary Free : Mint to Heath. 104 

 105. Ovary Adherent : Harebell to Honeysuckle. 106. Number Five! 



92. Division I. Apetalae. — Two Subdivisions: 

 (1) Ovary Adherent ; (2) Ovary Free. 



Subdivision I. Ovary Adherent. — Among 

 the lowest Orders here we see the Mistletoe 

 (Fig. 65). The flowers are always diclinous 

 and often dioecious. They have no pet- 

 als, but a flower-like calyx. The ovule 

 is without tegmen, or testa ; it consists 

 of the nucleus alone, and is often re- 

 duced to the embryo-sac, its only pro- 

 tection being the ovary, wliich is ad- 

 herent. And since the condition of the 

 embryo is the basis of classification (31), 

 this Order ranks lowest in Dicotyledons. 

 The female flower has 1 style, a 1-celled 

 ovary, and a 1 -seeded fruit. 



93. We know that the Mistletoe is a parasite. 

 Botanists suppose that long ago — it may have 

 been hundreds of thousands of year.? — it was a 

 climbing shrub, with roots in the ground, and 

 ascending trees by means of secondary roots like the Ivy. But the 

 underground root and the lower part of the stem perished in the 

 race for life ; and this strange creature of a prehistoric time lives on 

 as a true parasite. It sends its roots into the wood of its host, and 

 incorporates them so completely that they cannot be distinguished 

 from the fibre of the tree. It also adapts its seeds to its condition : 

 each seed usually has two embryos (Pig. 65, C) ; these protrude 

 from a nucleus without seed-coats ; and the ripe berry (pericarp) is so 

 viscid that the seeds cannot fail of a foothold on the host on which 

 they grow, or to which they may be borne by birds. And in order 

 to insure fertilization, the anther (B) is many-celled and honey- 



FlG. 65.— A, fis. of MiB- 

 t\etoe {ViNmm album). B, 

 antlier of J fl., ehoiving 

 the many pores. C, sec- 

 tion of sd., showing the 

 two embryos. D, yonug 

 plant. 



