248 On the Development of PhcEiiogammis Plants, 



every respect excepting the habitus, solely to be ascribed to 

 their locality, that I cannot find anything like a sufficient 

 ground to keep them disunited. It would certainly not occur 

 to any zoologist to separate an animal from its natural family 

 merely because it was a parasite : wherefore then should it be 

 otherwise with the vegetable kingdom* ? 



Explanation of the Engraving (Plate III.) 



Fig. 1 . A longitudinal section of the flower-bud of Taxus bacca {fc- 

 vtina). aa. leaves, b. the rudiment of the second integument, which forms 

 the berry, c. the first or inner integument, d. nucleus. 1 have repre- 

 sented the course of the epidermis by a fine line upon the ovule and the 

 two interior leaves, as likewise in figs. 4, 1 8, 22, and 23. 



Fig. 2. Longitudinal section of a very young pistil of Salvia Cliisii. 

 a. carpellary leaves, b. ovule, c. canal of the style. 



Fig. 3. The inferior portion of a newly impregnated ovule of Mirabilis 

 longifloray also a longitudinal section, a. funiculus, b. remains of the 

 nucleus, c. integumentum simplex, d. embryo-sac. e. pollen-tube, whose 

 extremity expands to form the embryo. /. an abortive pollen-tube. 



Fig. 4. Longitudinal section of a young ovule of Poli/gonum onentale. 

 a. nucleus, b. protuberance out of which the integumentum internum is 

 formed, c. commencement oi the integumentum externum. 



Fig. 5. A very minute ovule of Goodyera procera. a. integument, ex- 

 tern, b. integum. intern, c. remains of the nucleus, d. embryo-sac. 



Fig. 6 and 7- Early conditions of the embryo of Potamogeton lucens. 



Fig. 8. Potamogeton heterophyllus at a later period than the preceding. 

 a. plumula. b. cotyledon which is still unclosed {ungeschlossen). 



Fig. 9 — n. Different grades of development of the embryo oi Echiuni 

 vulgare. a. embryo-sac. b. embryo. 



Fig.' 12. Summit of the embryo-sac of Phormium tenax with the embryo 

 in course of development, a. embryo-sac. b. pollen-tube. c. embryo. 



Fig. 13 — 17. Formation of the embryo oi CEnothera crassipes. a. em- 

 bryo-sac. b. pollen-tube. c. embryo, d. terminal shoots {punct. vege- 

 tationis, WoliT). e. cotyledon. 



Fig. 18. Longitudinal section of the female flower of Pinus aUes, from 

 a cone about three quarters of an inch in length, a. carpellary leaf (brac- 

 tea of R. Brown), b. placenta (open ovarium of R. Brown), c. nucleus. 

 d. commencing integument {cupida auct.). e. embryo-sac. About this time 

 the carpellary leaf has already acquired its green colour, but the pilacenta 

 consists of colourless succulent cellular tissue. 



Fig. 19 — 23. Different periods in the development of Statice atropur- 

 purea. Fig. 19, interior of a very young bud. a, a. stdnwia. b. carpel- 

 lary leaves. Fig. 20, the same at a somewhat later period, a. four car- 

 pellary leaves, still disunited, b. commencement of the formation of the 

 ovule, c. base of the fifth carpellary leaf which has been cut off. Fig. 21, 

 a recent ovule, in which the first tumefaction for the development of the 

 inner integument is already evident. Fig. 22, longitudinal section of the 

 same at a later period. The inner integument a. has already extended it- 

 self over the entire nucleus A, whilst the external integument c. is scarcely 

 visible. Fig. 23, the same at a later period : a, by c, as before. 



Fig. 24. Longitudinal section of an ovule of Lathrcca squamaria soon 

 after its impregnation, a. iyitegumentum simplex, b. remains of the nu- 

 cleus (membrana nuclei, R. Brown), c. embryo-sac already filled with 



[* On this subject see Dr. Lindley's paper on the Botanical Aflinities 

 of Orobanchcy in our last volume, p,409. — Edit.] 



