Cf)e Crcrtfurg at 33otati]). 



[macr 



plain ; eight stamens, with beardless an- 

 thers : and nearly circular flat winged 

 seeds. The genus was named in honour 

 of the late Mr. McXab, of the Edinburgh 

 Botanic Garden. There is but a single spe- 

 cies, a Cape shrub, with the habit of a 

 l heath, having leaves in whorls of three, and 

 f flowers solitary or in pairs, borne by the 

 I shorter branches. [6. DJ 



MACODES Petola is a beautiful little 

 orchid from Java, belonging to the group 

 Physuridem. Its oval leaves are clouded 

 on the upper surface, and elegantly marked 

 with netted golden veins ; but its flowers 

 are small and inconspicuous, having free 

 conniving green sepals and thread-like 

 petals. As a genus, it is distinguished 

 from Myoda, one of its closest allies, by its 

 free lip ; and from another, Samaria, by 

 its column having a two-lobed appendage 

 at its base. [A. S.] i 



MACOYA. A Guiana name for Acrocomia 

 sclerocarpa. 



MACRADENIA latescens is a little Tri- 

 nidad orchid, forming a genus allied to 

 Oncidium, from which it differs by its cu- 

 cullate-concave undivided taper-pointed 

 lip, by its free perianth divisions, by its co- 

 lumn having the two lobes at its top con- 

 verging into a hood, and by its two fur- 

 rowless or unindented pollen-masses. The 

 plant is only about four inches high, and 

 has one-leaved pseudobulbs, from the base 

 of which arises a stalk bearing a raceme 

 of four or five dingy yellow flowers spotted 

 with brownish purple. [A. S.] 



MACRJEA. This name was given first 

 to a Chilian genus of Yivianiacece, which 

 proved to be identical with Yiviania ; and 

 afterwards to a composite plant from the 

 Galapagos Islands, which has since been 

 reduced to Lipochceta. The former is now 

 included by Bentham and Hooker in the 

 GerartiacecB, under which they place the 

 Yiviamece, as a minor group. 



MACRE. (Fr) Trapa natans. 



MACROCEPHALOUS. Big-headed ; the ! 

 term is sometimes applied to dicotyledon- ' 

 ous embryos whose cotyledons are con- J 

 solidatedL 



MACROPODAL, Big-footed ; applied by 

 t Richard to the embryo of grasses, whose 

 ' cotyledon was mistaken by that author for 

 a radicle. 



MACROS. In Greek compounds long ; 

 sometimes, large. 



MACROCHILUS. The name of a small 

 tree of the Sandwich Islands, forming a 

 genus of Lobeliaceee, and described as hav- 

 ing a straight trunk of ten to twelve feet 

 in height, terminated by a crown of leaves | 

 and flower stalks, the former sharp-pointed 

 and wavy, the latter longer than the leaves, ! 

 drooping, and bearing the flowers in ter- j 

 minal globose heads, surrounded by densely 

 overlapping bracts. The calyx tube is in- 

 versely conical, the limb five-cleft ; the 

 corolla has an elongated curved tube, cleft < 



on the upper side, and with a limb divided 

 into five equal linear pendulous segments, 

 whence the name of the genus, from ma- 

 cros, long, and cheilos, a lip. [M. T. M.] 



MACROCHLOA. A genus of grasses 

 belonging to the tribe Stipce, and included 

 by Steudel in the genus Stipa, of which it 

 forms a subsection. M. tenuissima and 

 M armaria are natives of the North of 

 Africa, Spain, and Portugal. [D M.] 



MACROCYSTIS. A remarkable genus 

 of dark-spored Algce, belonging to the na- 

 tural order Laminariacece. From a much- 

 branched root springs, in the first instance, 

 a small forked frond which alone bears the 

 fruit in clouded patches, the endochrome 

 of whose spore-cases ultimately breaks up 

 into four spores, as in many other lami- 

 narioid Alga. Besides this, however, arise 

 one or more tall slender steins, several feet 

 in length, with a vertical terminal lan- 

 ceolate frond, which is repeatedly split 

 from the base upwards in such a way as to 

 form new leaves, the attenuated base of 

 which gradually passes into a short petiole, 

 which becomes inflated above into a blad- 

 der. The original frond is thus repeatedly 

 divided in a secund manner, till the plant 

 becomes hundreds of feet long. As, how- 

 ever, the stem does not increase in strength 

 as the plant elongates, the strain is at 

 length so great, notwithstanding the nu- 

 merous bladders, that it at last gives way, 

 and the plant floats. Many species have 

 been proposed by authors, but all are redu- 

 cible to one, M.pyrifera, which girds the 



Macrocystis pyrifera var. luxurians. 



southern temperate zone, and stretches up 

 from thence along the Pacific to the Arctic 

 regions, through 120 degrees of latitude. 

 This plant, like the Sargassum, has been 

 celebrated by all voyagers, to whom it is of 

 great service in indicating the presence of 

 rocks, acting, as it does, like a great buoy. 

 Vast masses are thrown up on exposed 

 coasts, where it is rolled by the waves till 

 it forms cables as thick as a man's body. 

 Single plants have been estimated on rea- 

 sonable grounds as attaining a length of 

 700 feet. It is apparently indifferent to 

 cold, if not extreme, but inasmuch as like 



