PLATE XVIII.— COW-PARSNIP or HOGWEED (Heracleum Sphondylium). 



(Fig. 3 after Miiller.) 



Umbellifers are so named from the arrangement of their flowers, their stalks standing out from a central spot like the wires of an 

 umbrella. The Order is a very extensive one — including useful forms, such as Carrots and Parsnips, Celery and Parsley, or poisonous 

 forms, such as Hemlock and Fool's Parsley ; and in keeping with this distribution the attractions and inducements held out to insects are 

 neither few nor small. The flowers, though small individually, are associated together in such a way as collectively to present an imposing 

 appearance. Further, the outer flowers of the umbel have their corollas larger and much more developed than those towards the centre ; 

 so the outer flowers, with plenty of room to expand, attract insects by their size and thus entice them to visit the less conspicuous 

 flowers in the centre. Not only is there attraction, but there is inducement in the shape of honey. In the centre of each flower is a 

 ring-like disc secreting nectar, which is thus not only central in position but also circular, to admit of free access to it from any and 

 every part of the flower. As a further precaution against self-fertilisation the pollen is shed before the stigmas are ready to receive it. 



The Fruit of Umbellifers is very characteristic, and important for purposes of classification, and even the smell of the plant may be 

 of use in the same direction. 



Fig". 1. Inflorescence — a compound Umbel with numerous rays. The primary umbel usually possesses a few Bracts at its base, 

 and each of the secondary umbels a whorl of bracts. 



Fig. 2 a. Outer flower with the three outer Petals largely developed, and the two inner small. 

 b. Inner flower with all the Petals equally small. 



Fig". 3. Flower of Wild Chervil showing the first or Male condition, when the anthers are ripening and the stigmas still unde- 

 veloped ; and the more advanced or Female condition, when the stamens are gone and the stigmas appear. 



Fig. 4. Make vertical section of flower, between the two styles, to show insertion of parts. 

 Sepals, minute teeth arising from ovary. 

 Petals, inserted upon ovary. 



Stamens, inserted upon ovary, at the base of disc (not seen in this section). 

 Carpels with the flower-stalk prolonged between them. 

 Disc, at top of ovary and attached to styles. 



Diagram. — Calyx of five Sepals, represented by five small teeth. 

 Corolla of five free Petals, alternating with the sepals. 

 Andrcecium of five Stamens, alternating with petals. 

 Gyncecium of two united Carpels. 



Fig. 5. Stem — hairy, hollow except at the nodes, and grooved 



Fig. 6 and 7. The Foliage-leaves are large, and the leaf-stalk forms a sheath at its base. (Fig. 7 shows a leaf consisting wholly 

 of sheath.) 



Fig. 8. Bract, small and pointed 



Fig. 9. Stamen with curved Filament, attached to the back of the Anther by its tip. 



Fig. 10. Take an Ovary well-developed, and make a vertical section, cutting through the two styles, and a transverse section in 

 the region of the ovules. 



One Ovule in each chamber suspended from the top. 



Fig. 11. Fruit of two carpels, each containing a seed, and called a Cremocarp (Gr. cremos, I suspend). The forked axis in the 

 middle separates and suspends each half of the fruit, which is called a Mericarp (Gr. meros, a part). 



a. Outer face with five ridges and furrows between. 



( Two Marginal. 

 Ridges — < Two Intermediate. 



( One Median. 

 Furrows — In the underlying tissue are the four oil-canals. 



b. Inner face with two oil-canals. 



c. Occasionally there are five oil-canals on the outer face, and the fifth furrrow is made by the forking of the 



median ridge. 

 Fig. 12. If a Mericarp is soaked the cover can be easily removed, exposing the Seed Then the seed can be cut in two, 



showing the small embryo and large endosperm. 

 Fig. 13. Minute embryo may be turned out of seed with a needle and examined. 



CLASSIFICATION. 



Class. — Dicotyledon. 

 Division. — Poly petalse. 

 Sub-division. — Calyciflorse, 

 Order. — Umbelliferae. 



Stem, hollow except at nodes. 



Leaves, sheathing. 



Inflorescence, umbellate. 



Petals, five, inserted at base of disc. 



Stamens, five, incurved, inserted upon the ovary. 



Ovary, two-chambered. 



Ovules, pendent, one in each carpel 



Fruit, dry, indehiscent, separating into two, by the splitting of the longitudinal axis. 



Seed with endosperm. 



