Hello, I'm new to looking in the microscope and I'm stuck on the resin canal part of this i.d. We have been keying out a 2 needled pine with the bark, cone and habit of descriptions of pinus resinosa and pinus densiflora. We dissected a fat green needle in the hopes of seeing the resin canals on our sons amatuer microscope- They are there but they seem to count out at 10. Are resin canals a reliable diagnostic tool for pines? The botanical illustrations for densiflora (Japanese red pine) show 4 canals with a central vein that looks like a pigs nose...The botanical illustration for resinosa shows six canals with a vien that has two joined segments. Our needle cross section is a half circle with a oval central vein and I think 10 resin canals-Did we compress a circular vien in cutting it? Took many little slices and they are all that way...Can there be variation of resin canals within a type of pine? Thanks.. I have a long detailed explanation of the Pine of Mystery if that helps...
Welcome marguerite. Yes, 3-17 with P. nigra, according to Krussman's "Manual of Cultivated Conifers". An illustration in the book shows P. pinaster as having 10 resin canals ,maybe others do also. Pics of cones, bark, needles, habit and such may help somebody ID it. Mystery may help.
Can you do a drawing of the cross-section? The exact position of the canals is also important for identification, whether external (against the outer hypodermis), internal (touching the inner endodermis), medial (in the green tissue touching neither the hypodermis nor the endodermis), or septal (in the green tissue touching both the hypodermis and the endodermis; only found in a few subtropical pines).
TREE OF MYSTERY-DESCRIPTION OF A PINE.The tree is about 18 years old and over 30 feet tall. The growth intervals between branches vary from 3' at the bottom third to abut 1.5 feet towards the top. The overall habit of the tree limbs is strongly horizontal with new growth tipping up and the oldest growth dropping down. The tree holds its branches all the way to the ground.The trunks (a double) are straight. First year seed cones are 6 cm. and slightly assymetrical. There is no prickle and the apophyses is flat and oval. the umbo is glossy yellow green fading quickly after picking to yellow brown.The seed cones are held all the way around the branch and perpindicular to the branch. The lowest and most mature trunk bark is grey with vertical ridges but as the trunk ascends the bark flattens to a thin flaky red orange with some grey patterns.the 1/2-1 " branches have bark that is orange with a prickly scales and the more mature branches are grey with dark dots. The branchlets are orange with a 3 cm. terminal bud. There is a white cast over the newest terminal buds and the sheaths surrounding the bud. The needle sheath darkens to black with age. THE NEEDLES ARE HELD IN BUNDLES OF TWO. THEY ARE FLAT AND NOT OT ALL TWISTED. IN CROSS SECTION THEY ARE HALF A CIRCLE. THE NEEDLE SHEATH IS LESS THAN A CM. THE NEEDLE LENGTH IS A MEDIUM MATTE GREEN NOT PLASTIC OR SHINEY.THE NEEDLES ARE HELD ALL THE WAY AROUND THE BRANCHES. is this still a tree of mystery? thanks, marguerite
Hi agin, Will try to do the cross section but I'm not sure how to send it-this is my first time with on line posting..thank you!]
How long are the needles? If in the 8-15cm range, sounds most likely Pinus nigra, but there are other possibilities.
Michael, The needle length is between 7-11 cm. They are flat and a matt medium green. The mature bark is grey with vertical ridges but as the trunk ascends the bark flattens to a thin flaky red orange with some grey patterns. The small branches are orange with distinct scales (prickly) and 2" plus branches mature to a flat light gray bark with dots. The needles are held in bundles of 2. The overal habit of the tree is a straight trunk with horizontal branches- tipping slightly up with the new growth. thank you marguerite
Hello again- Here is a picture of the bark of the pine .Does this look like nigra? We got a confirmation on the resin canals -there are 8. Thank you Michael for tracking this-Marguerite
Where can i look up definitions of words describing the pine cone-such as appressed, rhombic and apex to describe the apophyses and mucronate to describe the umbo?-Marguerite
Yep! Not so easy! Different books tend to use slightly different terms. It can be quite tricky - quite often I only know what an author means through prior familiarity with what they are trying to describe. 'appressed' means flattened; 'rhombic' means diamond-shaped; 'apex' is just the tip. 'Mucronate' means with a very small spine.
Michael Thank you for your help with the pine i.d. I appreciate the responses you gave-trying to understand terminology and microscopes and posting pictures for the first time was hard. But it opened up a new world...Marguerite
