ANGIOSPERMAE 
237 
staminodes and the long-tubed blue fir. is visited almost solely by 
bees. The achenes of many sp. have hairs aiding wind-dispersal. 
Anemonopsis Sieb. et Zucc. Ranunculaceae (2). 1 sp. Japan. 
Anemopaegma Mart. Bignoniaceae (1). 25 sp. Braz. 
Anethum Tourn. = Peucedanum L. 
Angadenia Miers. Apocynaceae (iv. 4). 20 sp. trop. Am. 
Angelica (Riv.) Linn. Umbelliferae (6). 20 sp. N. temp, and N. Z. 
(p. 146). A . sylvestris L. in Brit. See Archangelica. 
Angelonia Humb. et Bonpl. Scrophulariaceae (11. 3). 24 sp. trop. Am. 
AngianthU3 Wendl. Compositae (iv). 22 sp. temp. Austr. Heads 
united into dense spikes or compound heads ( cf. Echinops). 
Angiopteris Hoffm. Marattiaceae (1). 1 sp. in many vars., A. evecta 
Hoffm., Madag., Indo-Mal. Large ferns with the sori not united 
into synangia as in most of the order. There is an annulus like that 
of Osmundaceae at the apex of the sporangium. The roots arise close 
to the apex and burrow downwards and outwards through the stem 
and the leaf-bases, emerging a good way down. 
Angiospermae. One of the two great divisions of Phanerogams or 
Spermaphytes, distinguished from the Gymnosperms by the fact that 
the carpels are invariably so infolded or arranged as to form an ovary 
in which the ovules are borne. Further, the endosperm is formed 
after fertilisation, instead of before it as in G. 
All A. possess true flowers, the essential parts of which are 
stamens and carpels. The former bear pollen sacs ( = micro-sporangia 
of Pteridophyta, q.v.), the latter ovules ( = mega-sporangia). [See 
Gymnosperms.] The pollen, in structure and development, closely 
resembles both the microspores of Pt. and the pollen of G. ; but in 
the carpels we find important differences. The ovule is always 
enclosed in the carpel; it (cf. fig. 9, p. 81) has 2 integuments (or 1) 
and in the nucellus we find as a rule one embryo-sac (more in some 
Chalazogams, Loranthaceae, &c.), in which is one ovum, at the 
upper (micropylar) end, not enclosed in an archegonium. On either 
side of it is another naked cell ; these two are usually regarded as 
abortive ova (synergidae). At the other end of the embryo-sac are 3 
cells (antipodal cells), commonly supposed to represent another egg- 
apparatus (the name often given to the ovum and synergidae) which 
is now entirely abortive. In the centre of the sac is the large central 
nucleus, formed as described on p. 80. Fertilisation occurs on the 
arrival of the pollen-tube, one of the male nuclei in it fertilising the 
ovum, the other uniting with the central nucleus or sometimes with 
the upper nucleus before it has fused with the lower. The zygote 
now forms the embryo, the central nucleus the endosperm (p. 104). 
Opinions differ as to the homologies of the cells in the embryo-sac, 
but the most favoured view is that cells formed before fertilisation 
together represent a ? prothallus (cf. Pteridophyta, Gymnospermae, 
and p. 54), whose full development into a nutritive body for the 
