comb] 



Ei)e Ereagurg of 3S0tauj?. 



318 



a panicle, are polygamous; calyx-tube ad- 

 hering to the ovary, above which it is con-" 

 stricted, thelimb bell-shaped ; petalsfour; 

 stamens eight. The fruit is leathery, with 

 four membranous wings, indehiscent and 

 one-seeded by the abortion of several of 

 the ovules. Many of the species are very 

 handsome. [J. T. S.] 



COMB-SHAPED. The same as Pecti- 

 nate. 



COMESPERMA. A genus of Polyga- 

 lacece, consisting of erect or twining 

 plants found in Australia and Tasmania, 

 and numbering about twenty species. It 

 is nearly related to the South American 

 genus Catocoma, but differs in the corolla 

 being composed of three united petals, in- 

 stead of five. The stems, which are not 

 much thicker than a crow-quill,are furnish- 

 ed with alternate leaves, mostly linear in 

 form. The flowers, disposed in axillary or 

 terminal racemes, either yellow, white, 

 blue or purple, the three latter colours 

 sometimes found in the same species, as 

 they are in our own common milkwort, 

 Polygala vulgaris, to whose flowers those 

 of the plants of this genus bear much re- 

 semblance, but are generally larger. The 

 calyx is five-lobed ; the corolla three- 

 lobed, the middle lobe largest ; the sta- 

 mens eight ; the ovary two-celled, crown- 

 ed with a curved style. The fruit is a 

 wedge-shaped capsule with two seeds, 

 each furnished with a tuft of silky hairs. 

 This latter circumstance gives rise to the 

 name of the genus. 



C. volubilis, the Blue-creeper of Tas- 

 mania, is a graceful little plant, twining 

 among other bushes and covering them 

 with its great abundance of beautiful blue 

 flowers. Its thin twining stems are fur- 

 nished with leaves which are between 

 linear and lance-shaped in form. This 

 plant grows in various parts of Australia, 

 as well as in Tasmania, and is universally 

 admired. It has been in cultivation in 

 England under the name Comesperma gra- 

 cilis. [A. A. B.] 



COMPRET. Symphytum officinale. 

 COM IN. (Fr.) Ervum Ervilia. 



COMMELYNACE.E. ( Spidenoorts.) A 

 natural order of hypogynous monocotyle- 

 dons, belonging to Lindley's xyridal alli- 

 ance. Herbs with flat leaves, usually 

 sheathing at the base. Outer perianth 

 (calyx) of three parts, herbaceous; inner 

 (corolla) also of three, coloured; stamens six 

 or three, the anthers opening on the side 

 next the pistil. Ovary three-celled with a 

 central placenta ; style one. Fruit a two to 

 three-celled capsule, opening by two or three 

 valves, which bear the dissepiments (par- 

 titions) on the middle ; seeds with a linear 

 hilum ; embryo pulley-shaped. Natives of 

 the East and West Indies, New Holland, 

 and Africa. A few are found in North 

 America, but none in Northern Asia or 

 Europe. The underground stems of many 

 of the plants yield starch, and are used for 

 food. The filaments of the Tradescantias 



have jointed hairs, in which a granular 

 movement is seen under the microscope. 

 There are sixteen known genera, and 260 

 species. The best known are Commelyna, 

 Tradescantia, and Cyanotis. [J. H. B.] 



COMMELYNA. The typical genus of the 

 order of spiderworts, distinguished by 

 having usually three petals, dropping early, 

 one of the three different in form from 

 the others, or wanting ; the filaments or 

 stalks of the anthers smooth and naked ; 

 the style or appendage on the seed vessel 

 i thread-like, and entire at the end. The 

 species are herbs, natives of tropical and 

 Northern America, East India, and NewHol- 

 land, having ovate or lance-shaped leaves, 

 and the flowers in groups, either issuing 

 from an involucre or sheath-like body, or 

 destitute of such covering, the former con- 

 stituting Commelyna proper, the latter 

 Aneilema. The genus was named in honour 

 of J. and G. Commelyn, well-known Dutch 

 botanists. The species are numerous, and 

 several have been long known in our col- 

 lections. They require various modes of 

 treatment, some being hardy, others re- 

 quiring a high temperatui-e. C. ccelestis, 

 notable for the delicate blue of the 

 flower, has oblong lanceolate leaves, and 

 the sheaths ciliated ; it is a half hardy 

 species, which under proper treatment 

 displays a succession of azure flowers 

 from July to September. One of more 

 recent introduction is C. scabra, a half 

 hardy perennial from Northern Mexico, 

 having straggling reddish stems, the 

 leaves lance-shaped, waved and hard at the 

 margin, and the flowers of a dull purple 

 brown. Dr. Lindley, in his Vegetable King- 

 dom, states that 'the fleshy rhizomes of 

 C. ccelestis, tuberosa, angustifolia, and stri- 

 ata, contain a good deal of starch mixed 

 with mucilage, and are therefore fit for food 

 when cooked. The Chinese employ those of 

 C. medico, as a remedy in cough,' &c. [G.D.] 



COMMIA. The name given to a plant of 

 Cochin-China, which forms a genus of Eu- 

 phorbiacece. This plant (not well known to 

 botanists) has been described by Loureiro 

 as a tree from which a white tenacious 

 gum exudes, said to be of a purgative and 

 emetic nature, and valuable in dropsy, but 

 requiring careful administration. The 

 leaves are stalked, lance-shaped, entire and 

 smooth. The inconspicuous flowers are 

 male and female on different plants: the 

 males in short axillary bracted spikes, 

 having neither calyx nor corolla, and the 

 stamens united into a column which bears 

 on its summit a number of anthers; the 

 females in terminal racemes having a 

 three-leaved calyx enclosing a three-lobed 

 ovary, crowned by three short recurved 

 styles. The fruit a three-celled capsule 

 with three seeds. [A. A. BJ 



COMMISSURE. The face by which two 

 carpels come together or cohere, as in 

 umbellifers. 



COMMON PETIOLE. The first and prin- 

 cipal leaf-stalk in compound leaves; the 

 secondary petioles are called partial. 



