324 Miscellaneous. 



In most of tho above species the ovules are very slowly deve- 

 loped, and their development is far from being completed when the 

 flower begins to wither, which is generally eight or ten days after 

 its opening. Hence in each flower the poUinic masses attain their 

 complete development long before the ovules, and may be destroyed 

 or carried away by insects, wind, or rain, without the ovules of the 

 flower being fertilized. But in the same inflorescence there are 

 flowers in all stages of evolution ; the lowest or oldest ones may 

 therefore be fecundated by the pollen of the higher or younger ones. 

 This is what usually takes place ; the ovaries at the bottom of the 

 inflorescence alone arrive at maturity. 



The ovary of the Orchids remains open in many species. The 

 upper part of its orifice, at the base of what is usually called the 

 stigma, is simply closed by tumefied or even liquefied epidermic cells, 

 forming the nectar, situated between the stigma and the base of the 

 labella. When the poUinic mass falls or is conveyed upon this 

 mucilage it is at once broken up into tetrads, and each grain of the 

 tetrad begins to germinate. 



The pollen germinates thus for a certain time : — two or three 

 days in Neottia ovata and Plataniliera hifolia, five or six days in 

 Orchis latifolia, seven or eight days in most of the other species, 

 and about nine or ten days in Loror/lossum liircinum and Ophrys. 

 When the poUen-tube reaches the nucule the latter projects 

 considerably beyond the integument; but when the contact has 

 taken place the ovule is rapidly developed and soon acquires its 

 definitive demensions. 



In our Orchidcse the vegetation is comparatively short (about six 

 weeks for the Neottia, six weeks or two months for most of the 

 species, and three or four mouths for Loroijhssum liircinum), and the 

 ovule takes twenty days or more for its complete formation, that is 

 to become fit for fecundation. The seed ripens in a much shorter 

 time. 



The pollen-tube does not reach tho ovule through the tissues of 

 the stigma or the carpels. Tho ovary is gaping, and through its 

 orifice the pollen-tubes pass united into a bundle, agglutinated by a 

 mucilage produced by the jellying of the superficial cells of the car- 

 pellar walls. This modification of the cells is caused by the advance 

 of the pollen-tube, and does not take place in ovaries which have not 

 been fecundated. — Comptes Jtendus, August 2, 1886, p. 357. 



Manual of North- American Birds. 

 We have received from Messrs. J. B. Lippincott & Co., of New 

 York, a notice that they are about to publish a ' Manual of North- 

 American Birds ' from the pen of Prof. Eobert Eidgway, whose 

 contributions to the literature of North-American ornithology are 

 well known. Prof. Ridgway's knowledge of the habits of birds in a 

 state of nature, and his connexion with the Ornithological Depart- 

 ment of the National Museum at Washington, will doubtless enable 

 him to make this a valuable contribution to the literature of orni- 

 thology. The work will be abundantly illustrated, the estimated 

 number of figures being 425. 



